bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-dimensional perovskite functionalized fiber-type heterostructured scintillators
Authors: Rogers E. G. , Birowosuto M. D. , Maddalena F. , Dujardin C. , Pagano F. , Kratochwil N. , Auffray E. , Krause P. , Bizarri G.
Published: February 2023

A fiber-type heterostructured scintillator based on bismuth germanate (Bi4Ge3O12) functionalized with the 2D-perovskite butylammonium lead bromide ((BA)2PbBr4) has been fabricated, and its scintillation performance analyzed toward its use for fast timing applications such as time-of-flight Positron Emission Tomography. The pixel shows energy sharing between the matrix and filler component, confirming that the two components are in synergy.
Sputtered terbium iron garnet films with perpendicular magnetic anisotropy for spintronic applications
Authors: Damerio S. , Avci C. O.
Published: February 2023

We report the structural, magnetic, and interfacial spin transport properties of epitaxial terbium iron garnet (TbIG) ultrathin films deposited by magnetron sputtering. High crystallinity was achieved by growing the films on gadolinium gallium garnet substrates either at high temperatures, or at room temperature followed by thermal annealing, above 750 °C in both cases. The films display large perpendicular magnetic anisotropy (PMA) induced by compressive strain, and tunable structural and magnetic properties through growth conditions or the substrate lattice parameter choice. The ferrimagnetic compensation temperature (TM) of selected TbIG films was measured through the temperature-dependent anomalous Hall effect in Pt/TbIG heterostructures. In the studied films, TM was found to be between 190 and 225 K, i.e., approximately 25-60 K lower than the bulk value, which is attributed to the combined action of Tb deficiency and oxygen vacancies in the garnet lattice evidenced by x-ray photoelectron spectroscopy measurements. Sputtered TbIG ultrathin films with large PMA and highly tunable properties reported here can provide a suitable material platform for a wide range of spintronic experiments and device applications.
Equivalent permeability model of dual-porosity and bi-dispersed porous media based on the intermingled fractal units
Authors: Liu Xiaohong , Wang Hongyu , Chang Liucheng
Published: February 2023

Dual-porosity and bi-dispersed porous media (DBPM) widely exist in geotechnical engineering, material engineering, soil science, and groundwater exploitation. Therefore, it is significant to quantify the relationship between permeability and matrix–fracture structure parameters for mastering fluid's seepage and transport characteristics. Hence, this paper derives an analytical solution of equivalent permeability for DBPM based on the intermingled fractal units (IFU). The developed model considers the capillary pressure of fractures and capillaries and the tortuosity of fractures and capillaries. Specifically, the number of porous matrix fractal units in IFU is quantified, and then, the dimensionless permeability is calculated, defined as the ratio of the permeability of np matrix fractal units to a single fracture fractal unit. The results reveal that equivalent permeability is mainly contributed by fracture permeability. Next, the second dimensionless permeability is defined to compare further and quantify the permeable ability of fracture and porous matrix. The results highlight that the permeability difference between a single fracture fractal unit and a single porous matrix fractal unit is approximately 7–11 orders of magnitude. Overall, through this paper, the preferential flow mechanism of DBPM can be better described and understood by introducing the above two dimensionless permeabilities and analyzing the influence of structural parameters on them.
Electrohydrodynamic viscous fingering of leaky dielectric fluids in a channel
Authors: Zhao Jiachen , Wang Zhongzheng , Gu Yuantong , Sauret Emilie
Published: February 2023

Viscous fingering is a commonly observed interfacial instability during fluid displacement, where a fingerlike shape is formed at the fluid interface when a more viscous fluid is displaced by a less viscous fluid. In this study, a hybrid numerical model based on the lattice Boltzmann method and finite difference method is developed for investigating the control of viscous fingering of leaky dielectric fluids confined in a channel using electrohydrodynamics. Extensive simulations are carried out for studying the effects of the strength and direction of the electric field as well as the fluid properties, including the permittivity ratio and conductivity ratio, on viscous fingering. It is shown that a horizontal electric field, i.e., when the direction of the electrical field is perpendicular to the direction of fluid motion, can either promote or suppress the viscous fingering, depending on the permittivity ratio and conductivity ratio. For a vertical electric field, the extent of promotion of viscous fingering first decreases and then increases with the increase in conductivity ratio at a constant permittivity ratio. Also, various interfacial morphologies, such as broad fingers and thin jets, are observed under different fluid properties. A phase diagram for both the horizontal and vertical electric field is established based on the simulations with different permittivity and conductivity ratios to characterize the interfacial morphologies. This study offers insight into the electrohydrodynamic effects on the viscous fingering of leaky dielectric fluids, which could facilitate the control of multiphase flow in various applications, such as enhanced oil recovery and coupled chromatographic systems for separation.
Heterogeneous integration of III–V semiconductor lasers on thin-film lithium niobite platform by wafer bonding
Authors: Zhang Xian , Liu Xiaoyue , Liu Lin , Han Ya , Tan Heyun , Liu Liu , Lin Zhongjin , Yu Siyuan , Wang Ruijun , Cai Xinlun
Published: February 2023

Thin-film lithium niobate (TFLN) photonic integrated circuits (PICs) have emerged as a promising integrated photonics platform for the optical communication, microwave photonics, and sensing applications. In recent years, rapid progress has been made on the development of low-loss TFLN waveguides, high-speed modulators, and various passive components. However, the integration of laser sources on the TFLN photonics platform is still one of the main hurdles in the path toward fully integrated TFLN PICs. Here, we present the heterogeneous integration of InP-based semiconductor lasers on a TFLN PIC. The III–V epitaxial layer stack is adhesively bonded to a TFLN waveguide circuit. In the laser device, the light is coupled from the III–V gain section to the TFLN waveguide via a multi-section spot size converter. A waveguide-coupled output power above 1 mW is achieved for the device operating at room temperature. This heterogeneous integration approach can also be used to realize on-chip photodetectors based on the same epitaxial layer stack and the same process flow, thereby enabling large-volume, low-cost manufacturing of fully integrated III–V-on-lithium niobate systems for next-generation high-capacity communication applications.
Soil physicochemical characteristics and leaf nutrient contents on banana farms of North Queensland, Australia
Authors: Orr Ryan , Northfield Tobin D. , Pattison Anthony , Nelson Paul N.
Published: February 2023

Context Banana production in Australia is in three primary sub-regions within tropical North Queensland and the industry faces a variety of challenges including costs of production, disease and pests, and environmental impacts. The range of soil characteristics and banana leaf nutrient status on banana farms has not previously been systematically described. This knowledge gap makes it difficult to adapt research, management recommendations, and regulations to the needs of the three primary growing sub-regions. Aims In this work, we aimed to identify key soil factors that differentiate growing sub-regions, and provide context for future research and industry regulation. Methods We characterised soil and banana leaf samples from 28 banana farms on soil types accounting for >85% of Australia’s banana production. Key results and conclusions Variation in soil properties and leaf nutrient concentrations were driven largely by site- (principal component 1 in both cases) and management-related variables (principal component 2 in both cases). Management-related foliar nutrient concentrations did not differ between regions despite differences in the associated soil variables. The most important site characteristics appeared to be soil parent material and climate. The Mareeba sub-region has basaltic soils, low rainfall and temperature, whereas the other two sub-regions are hotter, wetter and have a variety of soil parent materials. Leaf nitrogen concentrations were mostly below the regulated limit for additional nitrogen fertiliser application. Implications Our findings can facilitate sub-region-specific site selection for research, extension, and monitoring and more targeted regulation of banana production- and environment-related issues.
Functional polyamine metabolic enzymes and pathways encoded by the virosphere
Authors: Li Bin , Liang Jue , Baniasadi Hamid R. , Phillips Margaret A. , Michael Anthony J.
Published: February 2023

Viruses produce more viruses by manipulating the metabolic and replication systems of their host cells. Many have acquired metabolic genes from ancestral hosts and use the encoded enzymes to subvert host metabolism. The polyamine spermidine is required for bacteriophage and eukaryotic virus replication, and herein, we have identified and functionally characterized diverse phage- and virus-encoded polyamine metabolic enzymes and pathways. These include pyridoxal 5′-phosphate (PLP)-dependent ornithine decarboxylase (ODC), pyruvoyl-dependent ODC and arginine decarboxylase (ADC), arginase,
S
-adenosylmethionine decarboxylase (AdoMetDC/
speD
), spermidine synthase, homospermidine synthase, spermidine
N
-acetyltransferase, and
N
-acetylspermidine amidohydrolase. We identified homologs of the spermidine-modified translation factor eIF5a encoded by giant viruses of the
Imitervirales
. Although AdoMetDC/
speD
is prevalent among marine phages, some homologs have lost AdoMetDC activity and have evolved into pyruvoyl-dependent ADC or ODC. The pelagiphages that encode the pyruvoyl-dependent ADCs infect the abundant ocean bacterium
Candidatus Pelagibacter ubique
, which we have found encodes a PLP-dependent ODC homolog that has evolved into an ADC, indicating that infected cells would contain both PLP- and pyruvoyl-dependent ADCs. Complete or partial spermidine or homospermidine biosynthetic pathways are found encoded in the giant viruses of the
Algavirales
and
Imitervirales
, and in addition, some viruses of the
Imitervirales
can release spermidine from the inactive
N
-acetylspermidine. In contrast, diverse phages encode spermidine
N
-acetyltransferase that can sequester spermidine into its inactive
N
-acetyl form. Together, the virome-encoded enzymes and pathways for biosynthesis and release or biochemical sequestration of spermidine or its structural analog homospermidine consolidate and expand evidence supporting an important and global role of spermidine in virus biology.
Tracing energy inputs into the seafloor using carbonate sediments
Authors: Smith B. P. , Edie S. M. , Fischer W. W.
Published: February 2023

Carbonate rocks provide unique and valuable sedimentary archives for secular changes in Earth’s physical, chemical, and biological processes. However, reading the stratigraphic record produces overlapping, nonunique interpretations that stem from the difficulty in directly comparing competing biological, physical, or chemical mechanisms within a common quantitative framework. We built a mathematical model that decomposes these processes and casts the marine carbonate record in terms of energy fluxes across the sediment–water interface. Results showed that physical, chemical, and biological energy terms across the seafloor are subequal and that the energetic dominance of different processes varies both as a function of environment (e.g., onshore vs. offshore) as well as with time-varying changes in seawater chemistry and with evolutionary changes in animal abundance and behavior. We applied our model to observations from the end-Permian mass extinction—a massive upheaval in ocean chemistry and biology—revealing an energetic equivalence between two hypothesized drivers of changing carbonate environments: a reduction in physical bioturbation increased carbonate saturation states in the oceans. Early Triassic occurrences of ‘anachronistic’ carbonates—facies largely absent from marine environments after the Early Paleozoic—were likely driven more by reduction in animal biomass than by repeated perturbations to seawater chemistry. This analysis highlighted the importance of animals and their evolutionary history in physically shaping patterns in the sedimentary record via their impact on the energetics of marine environments.
Integrating comparative modeling and accelerated simulations reveals conformational and energetic basis of actomyosin force generation
Authors: Ma Wen , You Shengjun , Regnier Michael , McCammon J. Andrew
Published: February 2023

Muscle contraction is performed by arrays of contractile proteins in the sarcomere. Serious heart diseases, such as cardiomyopathy, can often be results of mutations in myosin and actin. Direct characterization of how small changes in the myosin–actin complex impact its force production remains challenging. Molecular dynamics (MD) simulations, although capable of studying protein structure–function relationships, are limited owing to the slow timescale of the myosin cycle as well as a lack of various intermediate structures for the actomyosin complex. Here, employing comparative modeling and enhanced sampling MD simulations, we show how the human cardiac myosin generates force during the mechanochemical cycle. Initial conformational ensembles for different myosin–actin states are learned from multiple structural templates with Rosetta. This enables us to efficiently sample the energy landscape of the system using Gaussian accelerated MD. Key myosin loop residues, whose substitutions are related to cardiomyopathy, are identified to form stable or metastable interactions with the actin surface. We find that the actin-binding cleft closure is allosterically coupled to the myosin motor core transitions and ATP-hydrolysis product release from the active site. Furthermore, a gate between switch I and switch II is suggested to control phosphate release at the prepowerstroke state. Our approach demonstrates the ability to link sequence and structural information to motor functions.
Polyamines and linear DNA mediate bacterial threat assessment of bacteriophage infection
Authors: de Mattos Camilla D. , Faith Dominick R. , Nemudryi Artem A. , Schmidt Amelia K. , Bublitz DeAnna C. , Hammond Lauren , Kinnersley Margie A. , Schwartzkopf Caleb M. , Robinson Autumn J. , Joyce Alex , Michaels Lia A. , Brzozowski Robert S. , Coluccio Alison , Xing Denghui David , Uchiyama Jumpei , Jennings Laura K. , Eswara Prahathees , Wiedenheft Blake , Secor Patrick R.
Published: February 2023

Monitoring the extracellular environment for danger signals is a critical aspect of cellular survival. However, the danger signals released by dying bacteria and the mechanisms bacteria use for threat assessment remain largely unexplored. Here
,
we show that lysis of
Pseudomonas aeruginosa
cells releases polyamines that are subsequently taken up by surviving cells via a mechanism that relies on Gac/Rsm signaling. While intracellular polyamines spike in surviving cells, the duration of this spike varies according to the infection status of the cell. In bacteriophage-infected cells, intracellular polyamines are maintained at high levels, which inhibits replication of the bacteriophage genome. Many bacteriophages package linear DNA genomes and linear DNA is sufficient to trigger intracellular polyamine accumulation, suggesting that linear DNA is sensed as a second danger signal. Collectively, these results demonstrate how polyamines released by dying cells together with linear DNA allow
P. aeruginosa
to make threat assessments of cellular injury.
Electrostatic-induced green and precise growth of model catalysts
Authors: Xia Qiancheng , Liu Bin , Wang Chao , Shen Tao , Li Shuang , Bu Yongguang , Zhang Yuchen , Lu Zhenda , Gao Guandao
Published: February 2023

Crystallographic control of crystals as catalysts with precise geometrical and chemical features is significantly important to develop sustainable chemistry, yet highly challenging. Encouraged by first principles calculations, precise structure control of ionic crystals could be realized by introducing an interfacial electrostatic field. Herein, we report an efficient in situ dipole-sourced electrostatic field modulation strategy using polarized ferroelectret, for crystal facet engineering toward challenging catalysis reactions, which avoids undesired faradic reactions or insufficient field strength by conventional external electric field. Resultantly, a distinct structure evolution from tetrahedron to polyhedron with different dominated facets of Ag
3
PO
4
model catalyst was obtained by tuning the polarization level, and similar oriented growth was also realized by ZnO system. Theoretical calculations and simulation reveal that the generated electrostatic field can effectively guide the migration and anchoring of Ag
+
precursors and free Ag
3
PO
4
nuclei, achieving oriented crystal growth by thermodynamic and kinetic balance. The faceted Ag
3
PO
4
catalyst exhibits high performance in photocatalytic water oxidation and nitrogen fixation for valuable chemicals production, validating the effectiveness and potential of this crystal regulation strategy. Such an electrically tunable growth concept by electrostatic field provides new synthetic insights and great opportunity to effectively tailor the crystal structures for facet-dependent catalysis.
A discrete intermediate for the biosynthesis of both the enediyne core and the anthraquinone moiety of enediyne natural products
Authors: Bhardwaj Minakshi , Cui Zheng , Daniel Hankore Erome , Moonschi Faruk H. , Saghaeiannejad Esfahani Hoda , Kalkreuter Edward , Gui Chun , Yang Dong , Phillips George N. , Thorson Jon S. , Shen Ben , Van Lanen Steven G.
Published: February 2023

The enediynes are structurally characterized by a 1,5-diyne-3-ene motif within a 9- or 10-membered enediyne core. The anthraquinone-fused enediynes (AFEs) are a subclass of 10-membered enediynes that contain an anthraquinone moiety fused to the enediyne core as exemplified by dynemicins and tiancimycins. A conserved iterative type I polyketide synthase (PKSE) is known to initiate the biosynthesis of all enediyne cores, and evidence has recently been reported to suggest that the anthraquinone moiety also originates from the PKSE product. However, the identity of the PKSE product that is converted to the enediyne core or anthraquinone moiety has not been established. Here, we report the utilization of recombinant
E. coli
coexpressing various combinations of genes that encode a PKSE and a thioesterase (TE) from either 9- or 10-membered enediyne biosynthetic gene clusters to chemically complement Δ
PKSE
mutant strains of the producers of dynemicins and tiancimycins. Additionally,
13
C-labeling experiments were performed to track the fate of the PKSE/TE product in the Δ
PKSE
mutants. These studies reveal that 1,3,5,7,9,11,13-pentadecaheptaene is the nascent, discrete product of the PKSE/TE that is converted to the enediyne core. Furthermore, a second molecule of 1,3,5,7,9,11,13-pentadecaheptaene is demonstrated to serve as the precursor of the anthraquinone moiety. The results establish a unified biosynthetic paradigm for AFEs, solidify an unprecedented biosynthetic logic for aromatic polyketides, and have implications for the biosynthesis of not only AFEs but all enediynes.
Terpene biosynthesis in marine sponge animals
Authors: Wilson Kayla , de Rond Tristan , Burkhardt Immo , Steele Taylor S. , Schäfer Rebecca J. B. , Podell Sheila , Allen Eric E. , Moore Bradley S.
Published: February 2023

Sea sponges are the largest marine source of small-molecule natural products described to date. Sponge-derived molecules, such as the chemotherapeutic eribulin, the calcium-channel blocker manoalide, and antimalarial compound kalihinol A, are renowned for their impressive medicinal, chemical, and biological properties. Sponges contain microbiomes that control the production of many natural products isolated from these marine invertebrates. In fact, all genomic studies to date investigating the metabolic origins of sponge-derived small molecules concluded that microbes—not the sponge animal host—are the biosynthetic producers. However, early cell-sorting studies suggested the sponge animal host may play a role particularly in the production of terpenoid molecules. To investigate the genetic underpinnings of sponge terpenoid biosynthesis, we sequenced the metagenome and transcriptome of an isonitrile sesquiterpenoid-containing sponge of the order Bubarida. Using bioinformatic searches and biochemical validation, we identified a group of type I terpene synthases (TSs) from this sponge and multiple other species, the first of this enzyme class characterized from the sponge holobiome. The Bubarida TS-associated contigs consist of intron-containing genes homologous to sponge genes and feature GC percentage and coverage consistent with other eukaryotic sequences. We identified and characterized TS homologs from five different sponge species isolated from geographically distant locations, thereby suggesting a broad distribution amongst sponges. This work sheds light on the role of sponges in secondary metabolite production and speaks to the possibility that other sponge-specific molecules originate from the animal host.
Fluorine-free mechanochemical synthesis of MXene
Authors: Ljubek Gabrijela , Kralj Magdalena , Kraljić Roković Marijana
Published: February 2023

MXene is a 2D transition metal carbide/nitride with excellent electrical, optical and mechanical properties. At present, most MXenes are prepared from the MAX phase by chemical etching with HF or HCl/LiF. This method is very limited in terms of large-scale production owing to the hazardous and toxic fluoride-containing reagents. There is an urgent need to explore safe and reliable synthetic methods to prepare MXene. In this short communication, we describe the mechanochemical route for preparation of the Ti3C2Tx from the Ti3AlC2. The prepared MXene has been studied by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV/Vis) spectrophotometry and Fourier-transform infrared spectroscopy. The results reported here have paved the way for new preparation methods for the fluorine-free MXenes.
Mechanism of external K+ sensitivity of KCNQ1 channels
Authors: Abrahamyan Astghik , Eldstrom Jodene , Sahakyan Harutyun , Karagulyan Nare , Mkrtchyan Liana , Karapetyan Tatev , Sargsyan Ernest , Kneussel Matthias , Nazaryan Karen , Schwarz Jürgen R. , Fedida David , Vardanyan Vitya
Published: February 2023

KCNQ1 voltage-gated K+ channels are involved in a wide variety of fundamental physiological processes and exhibit the unique feature of being markedly inhibited by external K+. Despite the potential role of this regulatory mechanism in distinct physiological and pathological processes, its exact underpinnings are not well understood. In this study, using extensive mutagenesis, molecular dynamics simulations, and single-channel recordings, we delineate the molecular mechanism of KCNQ1 modulation by external K+. First, we demonstrate the involvement of the selectivity filter in the external K+ sensitivity of the channel. Then, we show that external K+ binds to the vacant outermost ion coordination site of the selectivity filter inducing a diminution in the unitary conductance of the channel. The larger reduction in the unitary conductance compared to whole-cell currents suggests an additional modulatory effect of external K+ on the channel. Further, we show that the external K+ sensitivity of the heteromeric KCNQ1/KCNE complexes depends on the type of associated KCNE subunits.
Block delayed Majorize-Minimize subspace algorithm for large scale image restoration
*
Authors: Chalvidal Mathieu , Chouzenoux Emilie , Fest Jean-Baptiste , Lefort Claire
Published: February 2023

In this work, we propose an asynchronous Majorization-Minimization (MM) algorithm for solving large scale differentiable non-convex optimization problems. The proposed algorithm runs efficient MM memory gradient updates on blocks of coordinates, in a parallel and possibly asynchronous manner. We establish the convergence of the resulting sequence of iterates under mild assumptions. The performance of the algorithm is illustrated on the restoration of 3D images degraded by depth-variant 3D blur, arising in multiphoton microscopy. Significant computational time reduction, scalability and robustness are observed on synthetic data, when compared to state-of-the-art methods. Experiments on the restoration of real acquisitions of a muscle structure illustrate the qualitative performance of our approach and its practical applicability.
Synthesis of patchy particles using gaseous ligands
Authors: Virk Mudassar Mumtaz , Beitl Konstantin Nikolaus , van Oostrum Peter D J
Published: February 2023

The collective self-assembly of colloidal particles can be influenced by the composition of the suspending medium, the bulk material of the particles themselves and, importantly, by their surface chemistry. This can be inhomogeneous or patchy to give an orientational dependence to the interaction potential between the particles. These additional constraints to the energy landscape then steer the self-assembly towards configurations of fundamental or applicational interest. We present a novel approach to modify the surface chemistry of colloidal particles to give them two polar patches, using gaseous ligands. In particular, we synthesize polar inverse patchy colloids, i.e., charged particles with two (fluorescent) patches of the opposite charge on their poles. We characterize the dependence of these charges on the pH of the suspending solution.
First principle calculation of the photocurrent in a short carbon nanotube: the effect of an external bias
Authors: Zhang Yan , Chen Jingzhe
Published: February 2023

We studied the transport properties of a short carbon nanotube between two different metal electrodes. Specifically, the photocurrents under a series of bias voltages are investigated. The calculations are completed within the non-equilibrium Green’s function method, where the photon–electron interaction is taken as a perturbation. The rule-of-thumb that a forward bias decreases while a reverse bias increases the photocurrent under the same illumination is verified. The first principle results demonstrate the characteristic of the Franz–Keldysh effect, where the photocurrent response edge shows a clear red-shift trend in electric fields along both axial directions. An obvious Stark splitting is observed when some reverse bias is applied to the system due to the huge field strength. In this short-channel situation, intrinsic nanotube states are strongly hybridized with metal electrode states, which results in dark current leakage and specific features such as a long tail and fluctuations in the photocurrent response.
Effective doses and risks from medical diagnostic x-ray examinations for male and female patients from childhood to old age
Authors: Harrison John D , Haylock Richard G E , Jansen Jan T M , Zhang Wei , Wakeford Richard
Published: February 2023

The consideration of risks from medical diagnostic x-ray examinations and their justification commonly relies on estimates of effective dose, although the quantity is actually a health-detriment-weighted summation of organ/tissue-absorbed doses rather than a measure of risk. In its 2007 Recommendations, the International Commission on Radiological Protection (ICRP) defines effective dose in relation to a nominal value of stochastic detriment following low-level exposure of 5.7 × 10−2 Sv−1, as an average over both sexes, all ages, and two fixed composite populations (Asian and Euro-American). Effective dose represents the overall (whole-body) dose received by a person from a particular exposure, which can be used for the purposes of radiological protection as set out by ICRP, but it does not provide a measure that is specific to the characteristics of the exposed individual. However, the cancer incidence risk models used by ICRP can be used to provide estimates of risk separately for males and females, as a function of age-at-exposure, and for the two composite populations. Here, these organ/tissue-specific risk models are applied to estimates of organ/tissue-specific absorbed doses from a range of diagnostic procedures to derive lifetime excess cancer incidence risk estimates; the degree of heterogeneity in the distribution of absorbed doses between organs/tissues will depend on the procedure. Depending on the organs/tissues exposed, risks are generally higher in females and notably higher for younger ages-at-exposure. Comparing lifetime cancer incidence risks per Sv effective dose from the different procedures shows that overall risks are higher by about a factor of two to three for the youngest age-at-exposure group, 0–9 yr, than for 30–39 yr adults, and lower by a similar factor for an age-at-exposure of 60–69 yr. Taking into account these differences in risk per Sv, and noting the substantial uncertainties associated with risk estimates, effective dose as currently formulated provides a reasonable basis for assessing the potential risks from medical diagnostic examinations.
Removal of the effect of the high solids holdup ring in the fluidized bed on electromagnetic tomography
Authors: Wang Chao , Luan Xinyu , Liang Xiao , Ye Jiamin
Published: February 2023

Electromagnetic tomography (EMT) system based on tunneling magneto resistance (TMR) sensor, as a non-invasive multiphase flow measurement technique, can effectively detect the solid-phase distribution in the gas–liquid–solid three-phase fluidized bed with magnetic catalysts by reconstructing the permeability distribution image. The radial distribution of solid particles in the gas–liquid–solid three-phase fluidized bed with uneven fluidization is non-uniform, in which a high solids holdup ring exists near the wall of the riser. When the TMR-EMT system is used directly for image reconstruction, the high solids holdup ring will greatly reduce the image quality, further leading to the inability to detect phase information in the riser. To improve the reconstructed image by the TMR-EMT system, a removal method for the high solids holdup ring is proposed. The method firstly estimates the equivalent thickness of the high solids holdup ring based on the boundary measurement data. Then the influence of the high solids holdup ring on the boundary measurement data is subtracted. By the removal method, the internal phase distribution information is prominent. The simulation and experimental results demonstrate that the proposed method can realize the permeability distribution detection by the TMR-EMT system in the presence of the high solids holdup ring.
Application of nanofibrous protein for the purification of contaminated water as a next generational sorption technology: a review
Authors: Anani Osikemekha Anthony , Adama Kenneth Kennedy , Ukhurebor Kingsley Eghonghon , Habib Aishatu Idris , Abanihi Vincent Kenechi , Pal Kaushik
Published: February 2023

Globally, wastes from agricultural and industrial activities cause water pollution. Pollutants such as microbes, pesticides, and heavy metals in contaminated water bodies beyond their threshold limits result in several diseases like mutagenicity, cancer, gastrointestinal problems, and skin or dermal issues when bioaccumulated via ingestion and dermal contacts. Several technologies have been used in modern times to treat wastes or pollutants such as membrane purification technologies and ionic exchange methods. However, these methods have been recounted to be capital intensive, non-eco-friendly, and need deep technical know-how to operate thus, contributing to their inefficiencies and non-efficacies. This review work evaluated the application of Nanofibrils-protein for the purification of contaminated water. Findings from the study indicated that Nanofibrils protein is economically viable, green, and sustainable when used for water pollutant management or removal because they have outstanding recyclability of wastes without resulting in a secondary phase-pollutant. It is recommended to use residues from dairy industries, agriculture, cattle guano, and wastes from a kitchen in conjunction with nanomaterials to develop nanofibrils protein which has been recounted for the effective removal of micro and micropollutants from wastewater and water. The commercialization of nanofibrils protein for the purification of wastewater and water against pollutants has been tied to novel methods in nanoengineering technology, which depends strongly on the environmental impact in the aqueous ecosystem. So, there is a need to establish a legal framework for the establishment of a nano-based material for the effective purification of water against pollutants.
Boron nitride nanotube–salt–water hybrid:crystalline precipitation
Authors: Ge Yanyan , Zhang Cuicui , Zhu Xueru , Li Hua , Wang Yongjian
Published: February 2023

Molecular dynamics simulation is used to study the transport characteristics of NaCl solution in boron nitride nanotubes (BNNTs). It presents an interesting and well-supported MD study of the crystallization of NaCl from its water solution under the confinement of a 3 nm thick boron nitride nanotube with varied surface charging conditions. The results of the molecular dynamics simulation indicate that NaCl crystallization occurs in charged BNNTs at room temperature when the concentration of NaCl solution reaches about 1.2 M. The reason for this phenomenon is as follows: when the number of ions in the nanotubes is high, the double electric layer that forms at the nanoscale near the charged wall surface, the hydrophobicity of BNNTs, and the interaction among ions cause ions to aggregate in the nanotubes. As the concentration of NaCl solution increases, the concentration of ions when they aggregate in the nanotubes reaches the saturation concentration of the NaCl solution, resulting in the crystalline precipitation phenomenon.
Energy decay for wave equations with nonlinear damping and space-time coefficient in

Rn
Authors: Ogbiyele Paul A , Arawomo Peter O
Published: February 2023

In this paper, we consider the following nonlinear wave equation

u

t
t

−
Δ
u
+
a
(
t
,
x
)

|

u
t

|

m
−
1

u
t

+

|

u

|

p
−
1

u
=
0
,
t
>
0
,
x
∈

R

n

u
(
0
,
x
)
=

u
0

(
x
)
,

u
t

(
0
,
x
)
=

u
1

(
x
)
x
∈

R

n

and obtain optimal energy decay estimates under suitable assumptions on the space-time nonlinear damping coefficient a, where m satisfies

1
<
m
⩽

n
+
2

n
−
2

. We establish a new Liapunov type function to obtain energy decay estimates in the case of nonlinear damping instead of the Kormonik lemma.
Multi-valued random dynamics of partly dissipative reaction–diffusion system with discontinuous nonlinearity on

RN
Authors: Ma Zhong-Xin , Zhao Jia-Cheng
Published: February 2023

This paper is devoted to studying a system consisting of a reaction–diffusion equation with multi-valued right-hand side and an ordinary differential equation in absence of dissipation term, which is defined on the whole space

R

N

. The system is driven by time-dependent forces and coloured noise with nonlinear diffusion. We first establish the global existence of strong/mild solutions for initial-value problems. The measurability of solution map with respect to sample points and initial values is then obtained via the upper semicontinuity, which indicates that these solutions define a (non-autonomous) multi-valued random dynamical system. Finally, we prove the existence of pullback attractor for the dynamical system.
Edge effect reduction of high-resolution PET detectors using LYSO and GAGG phoswich crystals
Authors: Liu Zheng , Mungai Samuel , Niu Ming , Kuang Zhonghua , Ren Ning , Wang Xiaohui , Sang Ziru , Yang Yongfeng
Published: February 2023

Objective. Small-animal positron emission tomography (PET) is a powerful preclinical imaging tool in animal model studies. The spatial resolution and sensitivity of current PET scanners developed for small-animal imaging need to be improved to increase the quantitative accuracy of preclinical animal studies. This study aimed to improve the identification capability of edge scintillator crystals of a PET detector which will enable to apply a crystal array with the same cross-section area as the active area of a photodetector for improving the detection area and thus reducing or eliminating the inter-detector gaps. Approach. PET detectors using crystal arrays with mixed lutetium yttrium orthosilicate (LYSO) and gadolinium aluminum gallium garnet (GAGG) crystals were developed and evaluated. The crystal arrays consisted of 31 × 31 array of 0.49 × 0.49 × 20 mm3 crystals; they were read out by two silicon photomultiplier arrays with pixel sizes of 2 × 2 mm2 that were placed at both ends of the crystal arrays. The second or first outermost layer of the LYSO crystals was replaced by GAGG crystals in the two crystal arrays. The two crystal types were identified using a pulse-shape discrimination technique to provide better edge crystal identification. Main results. Using the pulse shape discrimination technique, almost all (except for a few edge) crystals were resolved in the two detectors; high sensitivity was achieved by using the scintillator array and the photodetector with the same areas and achieved high resolution by using crystals with sizes equal to 0.49 × 0.49 × 20 mm3. Energy resolutions of 19.3 ± 1.8% and 18.9 ± 1.5%, depth-of-interaction resolutions of 2.02 ± 0.17 mm and 2.04 ± 0.18 mm, and timing resolutions of 1.6 ± 0.2 ns and 1.5 ± 0.2 ns were achieved by the two detectors, respectively. Significance. In summary, novel three-dimensional high-resolution PET detectors consisting of a mixture of LYSO and GAGG crystals were developed. The detectors significantly improve the detection area with the same photodetectors and thus improve the detection efficiency.
In situ probing of atmospheric-pressure warm air glow discharge for nitrogen fixation by multiple laser spectroscopies
Authors: Shu Zhan , Qiao Junjie , Yang Qi , Song Yijia , Wang Dazhi , Xiong Qing
Published: February 2023

The fixation of atmospheric nitrogen into valuable compounds through reactive plasma processes has attracted intense interests due to its easy operation and compatibility with distributed renewable energy sources. However, practical implementation of plasma-assisted nitrogen fixation is hampered because of its relatively low throughput, which is dominantly limited by the unclear underlying mechanisms. In this study, effort was focused on the in situ production of key species in a DC-driven warm air glow discharge at atmospheric pressure with the help of advanced laser spectroscopic diagnostics. Laser Rayleigh scattering was applied to determine the gas temperature distribution in the discharge column. And mid-infrared quantum cascade laser absorption spectroscopy and one/two-photon absorption laser-induced fluorescence were performed on molecular nitric oxide (NO), atomic oxygen and nitrogen (O, N) for their absolute densities in the discharge. It is found that the spatial distributions of gas temperature, O and N atoms show peaks in the hot discharge center. In contrast, a hollow ‘doughnut’ shape characterized by the NO molecule was observed, particularly under conditions of high discharge current but low airflow rate. The steady-state simulation shows that the hollow pattern of NO is dominantly induced by the radial diffusion of species due to the steep spatial gradient of gas temperature in the discharge cross-section. Moreover, the reverse conversion by atomic N leads to a negative effect on the NO synthesis, especially at the discharge center where the N density and gas temperature are high. From the steady-state modeling, a similar hollow distribution of NO2 was depicted in the air glow discharge. These results demonstrate the strong dependence on atomic O for the major formation process of NO, and the importance of suppressing the reverse paths dominated by atomic N for higher NO production in the studied warm air plasma.
Remarks on physics
Authors: Paul Harry
Published: February 2023

I compare and contrast classical and quantum descriptions and then argue that even the celebrated stability of matter following from the Schrödinger equation is based on ad-hoc assumptions.
Effect of negative triangularity on peeling-ballooning instability
Authors: Qin Chenchen , Mou Maolin , Chen Shaoyong , Li Yongjian , Luo Yang , Zhu Limin , Dong Liangkang , Tang Changjian
Published: February 2023

Experiments have achieved high confinement discharges in tokamaks with a negative triangularity (NT) plasma shape accompanied by a lower pedestal and smaller and more frequent edge localized modes (ELMs) compared with positive triangularity (PT). Some existing theories emphasize the linear instability variations result from the change of pedestal. However, NT can directly bring significant changes on magnetic field structures which may also influence the instability of ELMs. Based on a series of equilibria constructed with different triangularities and pressure profiles, the influence of NT on peeling-ballooning mode (P–B mode) is investigated. It is found that NT can increase the growth rates of low to intermediate n (toroidal mode number) modes in the linear stage and lead to a larger pedestal collapse in the nonlinear stage if its pressure profile is the same with the PT shape. Further analyses demonstrate that NT enlarges the unfavorable curvature area, which provides stronger driving source and larger unstable region for the instability. Meanwhile, the diamagnetic effect and local magnetic shear helps to stabilize high n modes in the linear phase, and the E × B shearing rate at the top of the pedestal contributes to suppress the transport of turbulence into the plasma core in the nonlinear phase for the NT shape. What’s more, further simulations with different pedestal heights demonstrate that there exists a threshold value of pressure ratio, below which the ELM energy loss in NT shapes can be smaller than that in PT shapes, suggesting that the smaller energy loss with NT in experiment mainly results from the lower pedestal heigh. The results reveal behaviors of P–B modes and provide possible mechanisms for the phenomenon of lower pedestal height with negative triangularities in experiments.
First-principles study of crystal structure search, stability and mechanical property of magnesium-lithium binary system
Authors: Zhang Xiaozhe , Huang Yan , He Xiaoguang , Sun Shaodong
Published: February 2023

In this paper, the energetically stable and metastable crystal structures of Mg-Li binary system are searched throughout all possible Mg concentrations by using the first-principles calculations based on density functional theory (DFT). Three stable structures are found at compositions LiMg, LiMg2 and Li2Mg3. One metastable structure is found at composition LiMg3. The formation energy, phonon spectrum, and elastic constants are calculated to evaluate the energy, dynamic and elastic stabilities, respectively. At zero temperature, both the elastic moduli (include bulk modulus B, shear modulus G, Young’s modulus E, the Poisson’s ratio ν and B/G ratio) as a function of the Mg concentration in Mg-Li binary system and the spatial direction dependences of elastic moduli are analyzed. The temperature dependents of bulk modulus and thermal expansion coefficient are also analyzed to investigate the high-temperature mechanical properties of Mg-Li binary system. With the increase of temperature, the bulk modulus of Mg-Li alloys gradually decreases and the thermal expansion coefficient gradually increases. And the calculated results also show that LiMg2 can maintain excellent mechanical strength and mechanical stability at high temperature, and has the potential of application in the high-temperature fields.
Observations of xenon spectra on the EAST x-ray crystal spectrometer for high-temperature plasma diagnostics
Authors: Lu Dian , Wang Fudi , Delgado-Aparicio Luis F. , Yang Yang , Hill Kenneth , Bae Cheonho , Bitter Manfred , Fu Jia , Zhang Hongming , Shen Yongcai , Jin Yifei , Liu Haijing , He Liang , Fu Shengyu , Zang Qing , Lyu Bo
Published: February 2023

The Xe44+ 2.7203 Å line, which has been proposed as one of the diagnostic lines for the x-ray imaging crystal spectrometer on ITER, is observed on the EAST tokamak together with its several satellite lines. The observations are made under high electron temperature (T

e
) conditions (core T

e
> 5 keV). Most of the observed xenon lines are identified by comparing the experiment results with the atomic simulation results. The first ion temperature measurements made by the xenon spectra on EAST are also reported in this article. These xenon spectra observations contribute to the justification for using xenon as the diagnostic impurity in x-ray crystal spectrometers in future reactor-scale high-temperature plasmas.
Features of the combined technology based on laser metal deposition with layered laser heat treatment
Authors: Zavalov Y N , Dubrov A V , Rodin P S , Makarova E S , Dubrov V D
Published: February 2023

The results of combined using of laser metal deposition technology with layer-by-layer laser heat treatment technology are presented and the experimental setup is described to unite the laser metal deposition technology with layer-by-layer laser remelting and/or laser surface hardening implementation. The layers formed at the stages of laser metal deposition and additional layer-by-layer laser heat treatment alternate in the material. The ratio between the thicknesses of the layers obtained during crystallization at the laser metal deposition stage and at the laser remelting stage is shown to vary widely depending on the technological parameters. The surface temperature of the irradiated layer is maintained in laser surface hardening mode in the range of 1100 °C – 1400 °C with present laser power function. It is proposed to use this mode for local structural-phase transformation of the material.
Study and comparison of resist characteristics for different negative tone electron beam resists
Authors: Andok R , Vutova K , Bencurova A , Kostic I , Koleva E
Published: February 2023

In this work, four types of negative electron beam resists are investigated. Electron beam lithography (EBL) experiments were conducted using EBL system ZBA23 (Raith) with the variable-shaped electron beam cross-section at 40 keV electron energy. Important electron beam resist characteristics such as sensitivity, dissolution rate, aspect ratio and sidewall developed profiles in the chemically amplified resist (CAR) SU-8 2000, non-CARs ma-N 2410 and ARN-7520, and inorganic negative resist HSQ XR-1514 are studied and compared. This study was motivated by the selection of a suitable resist for practical use such as large area gratings fabrication for optoelectronics.
Study of double electron beam refining at melting of hafnium metal sponge
Authors: Vutova K , Vassileva V , Ratheesh R , Reddy R C , Kumar A
Published: February 2023

The possibility of the refining of hafnium metal sponge by e-beam double melting process is studied in this work. For this purpose, the effect of kinetic and thermodynamic parameters on the behavior of the impurities present in the base metal and their influence on the microstructure of the samples produced after double electron beam refining are investigated. The vapor (partial) pressure of hafnium, the controlled metallic inclusions (impurities) and their oxides as well as the relative volatility for the inclusions in the investigated hafnium material were evaluated. The process efficiency and the degree of refining with respect to the controlled impurities for each technological mode at double refining of hafnium sponge material were assessed based on thermodynamic analysis and conducted experiments.