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Segregation of the solidification structure of an immiscible alloy is related to the convection induced by the density differences of the components under gravity during solidification. Here, the solidification of the Al–Bi alloy in both opposing and parallel directions to the gravity force was investigated in situ using radiography and optical flow techniques. A quantitative analysis was performed on the flow, solute, and constitutional undercooling fields at the interface. During upward solidification, a flat solute-enriched layer was observed, with the melt flowing toward the center from both sides of the interface. During downward solidification, the solute-enriched layer was deformed, and solute plumes were observed, with the melt flowing toward the sides from the center of the interface. A high solute concentration gradient enhances the local flow and solute transport. The elongation of the plumes was attributed not only to the convective diffusion of the solute but also to the dispersion of droplet clusters. The forces acting on the droplets were calculated, and it was found that the resultant force on the droplets increased the area of the solute-enriched layer. Convection within the bulk melt and the motion of the droplets have synergistic effects on the flow pattern and solute distribution. Distinct microstructures were observed in opposite directions of solidification owing to the differences in constitutional undercooling and flow instability. This work offers insights into the quantitative measurement and understanding of the multi-physics fields during the solidification process. [ABSTRACT FROM AUTHOR]

Cuttage is a common plant cultivation method, and the key to its survival is the restoration of water refilling, which remains unclear up to now. We report 3D dynamic imaging of water refilling of cuttage without resorting to any contrast agent. Hydrodynamics of the refilled water flow over time reveals the existence of a unit mass force field with a gradient along the refilling direction, which means that cutting plants also have a gradient force field to drive the recovery of water refilling, as predicted by Cohesion-Tension theory in normal plants. We found that force fields of different functional regions are isolated and independently distributed, which is conducive to ensure the safety of water transmission. At the same time, we also found that there is a so-called "inchworm effect" in the mass force field, which contributes to the force transfer inside the cutting through local force accumulation. Results of this paper demonstrate that the developed method for the measurement of mass force field in-vivo is applicable to help decipher the mechanism of plant water refilling. [ABSTRACT FROM AUTHOR]

The growth of lithium dendrites and the shuttle of polysulfides in lithium metal batteries (LMBs) have hindered their development. In LMBs, the cathode and anode are separated by a separator, although this does not solve the battery's issues. The use of biomass materials is widespread for modifying the separator due to their porous structure and abundant functional groups. LMBs perform more electrochemically when lithium ions are deposited uniformly and polysulfide shuttling is reduced using biomass separators. In this review, we analyze the growth of lithium dendrite and the shuttle of polysulfide in LMBs, summarize the types of biomass separator materials and the mechanisms of action (providing mechanical barriers, promoting uniform deposition of metal ions, capturing polysulfides, shielding polysulfide). The prospect of developing new separator materials from the perspective of regulating ion transport and physical sieving efficiency as well as the application of advanced technologies such as synchrotron radiation to characterize the mechanism of action of biomass separators is also proposed. [ABSTRACT FROM AUTHOR]

Returning extraterrestrial samples to Earth has become essential for future deep space exploration. Achieving a comprehensive evaluation of the physical and chemical properties of samples with minimal damage is key to analyzing extraterrestrial samples in the future, as well as to the future sampling and returning of heterogeneous solid samples. This article aims to reconstruct the three-dimensional internal structure of high-contrast objects, select sections of interest through internal structure and detail features, and then analyze the physical and chemical properties of the samples based on laser spectroscopy technology. This paper proposes a strategy based on Raman mapping and X-ray phase-contrast imaging technology to reconstruct the three-dimensional internal structure of a heterogeneous solid sample and detect the substance composition of the region of interest. This study takes meteorite samples as an example and uses X-ray phase-contrast imaging technology to distinguish and reconstruct the spatial distribution of different components in the meteorite, providing a three-dimensional visualization reference with a high spatial resolution for the spatial positioning of the region of interest. Raman spectroscopy, in combination with LIBS, was used to further identify the meteorite as pallasite and to achieve the spectral image fusion of high spatial and high spectral resolutions. The experimental results show that the unknown meteorite's three-dimensional structure and its components' spatial distribution can be evaluated based on Raman mapping combined with X-ray phase-contrast imaging technology. This article provides a highly valuable analytical strategy by which to analyze samples returned from deep space exploration. [ABSTRACT FROM AUTHOR]

In this work, the influence of Si concentration on the microstructure and growth of plasma electrolytic oxidation (PEO) coatings on two types of Al–Si–Mg aluminum alloys were investigated. we utilized a multiscale correlative methodology to analyze the microstructure and micro-defect characteristics of the PEO coatings formed on A357 and 6082 aluminum alloys. The results demonstrate that both coatings exhibit a porous structure and are primarily composed of alumina and amorphous phases. Notably, the PEO coating formed on A357 alloy exhibits lower thickness, higher porosity, and more non-uniform barrier layer compared to that on 6082 alloy due to a higher concentration of Si in the substrate. Advanced X-ray computed tomography effectively characterizes micro-defects with different morphologies within the two coatings. Through microstructural observation and micro-defect characterization, we elucidate the influence of Si on the coating growth. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile‐based carbon fibers (CFs) have demonstrated unparalleled physical and mechanical properties and are considered a promising material for aerospace, transportation, medical devices, and other applications. However, the current understanding of the heterogeneous structure of carbon fiber is still vague, and the relationship between the heterogeneous structure and the mechanical properties of carbon fiber is also unclear. In this review, the literature on the radial heterogeneous structure of CFs is summarized from four points of view: morphological structure, physical properties and chemical structures, mechanical properties, and structural models by combining different characterization tools such as nanoindentation, nanoscale infrared spectroscopy, and synchrotron wide‐angle X‐ray diffraction. First, the size and orientation of graphite microcrystalline, the degree of graphitization, density distribution, modulus distribution, chemical functional group distribution, and other physical and chemical properties of carbon fiber cross‐sectional structures are discussed. Afterward, the relationship between the mechanical properties of carbon fiber and the heterogeneous structure is analyzed. Finally, the currently accepted models of the heterogeneous structure of carbon fibers are summarized and made some suggestions for research on the heterogeneous structure of carbon fibers. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of defects on tensile failure of additive manufactured AlSi10Mg alloy focusing particularly on the role of large pancake shaped loss of fusion (LOF) defects lying perpendicular to the build direction (BD). Time-lapse in situ synchrotron radiation X-ray micro-computed tomography during straining reveals how, when tested parallel to the BD, the LOF defects extend laterally with straining connecting to other defects and giving rise to low plasticity and an essentially brittle failure mode. When they are aligned edge-on to the straining direction, failure is characterised by a ductile cup-cone failure with significant elongation of the defects axially and extensive necking prior to failure. The soft fish-scale melt pool boundaries were also found to affect the fracture path. These results highlight the anisotropic effect of loss of fusion defects in controlling tensile ductility and the need to minimize their size and aspect ratio. In cases where these cannot be fully eliminated the component should be fabricated such that the BD is not aligned with the dominant in-service loading direction. [ABSTRACT FROM AUTHOR]

Several human host proteins play important roles in the lifecycle of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Many drugs targeting these host proteins have been investigated as potential therapeutics for coronavirus disease 2019 (COVID‐19). The tissue‐specific expressions of selected host proteins were summarized using proteomics data retrieved from the Human Protein Atlas, ProteomicsDB, Human Proteome Map databases, and a clinical COVID‐19 study. Protein expression features in different cell lines were summarized based on recent proteomics studies. The half‐maximal effective concentration or half‐maximal inhibitory concentration values were collected from in vitro studies. The pharmacokinetic data were mainly from studies in healthy subjects or non‐COVID‐19 patients. Considerable tissue‐specific expression patterns were observed for several host proteins. ACE2 expression in the lungs was significantly lower than in many other tissues (e.g., the kidneys and intestines); TMPRSS2 expression in the lungs was significantly lower than in other tissues (e.g., the prostate and intestines). The expression levels of endocytosis‐associated proteins CTSL, CLTC, NPC1, and PIKfyve in the lungs were comparable to or higher than most other tissues. TMPRSS2 expression was markedly different between cell lines, which could be associated with the cell‐dependent antiviral activities of several drugs. Drug delivery receptor ICAM1 and CTSB were expressed at a higher level in the lungs than in other tissues. In conclusion, the cell‐ and tissue‐specific proteomics data could help interpret the in vitro antiviral activities of host‐directed drugs in various cells and aid the transition of the in vitro findings to clinical research to develop safe and effective therapeutics for COVID‐19. [ABSTRACT FROM AUTHOR]

Electrocatalytic performance of low-cost graphitic carbon nitride (CN) is greatly limited by its limited conductivity and small specific surface area. Herein, a simple and cost-effective idea to produce novel nanocomposite is constructed by the CN and cetyl trimethyl ammonium bromide functionalized carbon black (CB) anchored platinum nanoparticles as highly efficient oxygen reduction catalysts based on gamma irradiation. The assembled carbon nitride/positive carbon black anchoring PtNPs (Pt/CN2-CB+1) catalyst exhibits significantly improved specific surface area, high graphitization, and uniformly dispersed ultra-small platinum nanoparticles. For the oxygen reduction reaction (ORR) performance, the catalyst shows more positive onset-potential (0.93 V versus RHE) and larger diffusion limiting current density (5.65 mA cm−2) compared with benchmark Pt/C catalysts in alkaline medium. Moreover, the Pt/CN2-CB+1 catalyst exhibits a small Tafel slope (92 mV dec−1). Besides, the catalyst was demonstrated the remarkable methanol tolerance and good long-term stability under working conditions. This work provides a new and effective γ-rays irradiation for synthesizing the carbon nitride catalysts for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

Alcohol dependence (AD) presents cognitive control deficits. Event-related potential (ERP) P300 reflects cognitive control-related processing. The aim of this study was to investigate whether cognitive control deficits are a trait biomarker or a state biomarker in AD. Participants included 30 AD patients and 30 healthy controls (HCs). All participants were measured with P300 evoked by a three-stimulus auditory oddball paradigm at a normal state (time 1, i.e., just after the last alcohol intake) and abstinence (time 2, i.e., just after a 4-week abstinence). The results showed that for P3a and P3b amplitude, the interaction effect for group × time point was significant, the simple effect for group at time 1 level and time 2 level was significant, and the simple effect for time point at AD group level was significant; however, the simple effect for time point at HC group level was not significant. Above results indicated that compared to HCs, AD patients present reductions of P3a/3b amplitude, and after 4-week alcohol abstinence, although P3a/3b amplitudes were improved, they were still lower than those of HCs. For P3a and P3b latencies, no significant differences were observed. These findings conclude that AD patients present cognitive control deficits that are reflected by P3a/3b and that cognitive control deficits in AD are trait- and state-dependent. The implication of these findings is helpful to understand the psychological and neural processes for AD, and these findings suggest that improving the cognitive control function may impact the treatment effect for AD. [ABSTRACT FROM AUTHOR]

The average nicotine half-life in body tissues is 2 h. Understanding the influence of pure nicotine abstinence on cognitive control may be helpful in eliminating nicotine dependence (ND) and preventing smoking relapse. This study was to investigate the effects of 2-h tobacco abstinence on cognitive control in patients with ND. Twenty-five patients with ND completed event-related potential (ERP) P300 measurements at the normality state and the abstinence state. Twenty-five healthy controls (HCs) were measured with P300 twice with a 2-h time interval. HAMD and HAMA were used to assess the emotional state. Results showed that there were significant differences in Carbon monoxide (CO) levels between the abstinence state and the normality state in the ND group. There were no significant differences in HAMD and HAMA scores for the abstinence state in the ND group or the normality state in the ND group and the HC group. For P3a, P3b amplitude, and P3a latency, the main effect for ND group was significant. For P3a, P3b amplitude, and latency, the interaction effect for group × time point was not significant, and the main effect for time point was not significant. It concluded that patients with ND present cognitive control deficits, and 2-h tobacco abstinence has no effect on cognitive control deficits in male patients with ND. Our findings may be helpful in eliminating nicotine dependence and preventing smoking relapse. [ABSTRACT FROM AUTHOR]

Inorganic arsenic (iAs) is a well-known naturally occurring metalloid with abundant hazards to our environment, especially being a human carcinogen through arsenic-contaminated drinking water. The iAs-related contamination is usually examined by a chemical assay system or fluorescence staining technique to investigate iAs accumulation and its deleterious effects. In this work, we present a dual-modality measurement and quantitative analysis methods for the overall evaluation of various dose-dependent iAs-related cytotoxicological manifestations by the combination of the synchrotron-radiation-based scanning transmission soft X-ray microscopy (SR-STXM) and Fourier transform infrared micro-spectroscopy (SR-FTIR) techniques. The gray level co-occurrence matrix (GLCM) based machine learning was employed on SR-STXM data to quantify the cytomorphological feature changes and the dose-dependent iAs-induced feature classifications with increasing doses. The infrared spectral absorption peaks and changes of dose-dependent iAs-induced cells were obtained by the SR-FTIR technique and classified by the multi-spectral-variate principle component analysis (PCA–LDA) method, showing the separated spatial distribution of dose-dependent groups. In addition, the quantitative comparisons of trivalent and pentavalent iAs under high dose conditions (iAsIII_H & iAsV_H) demonstrated that iAsIII_H and its compounds were more toxic than iAsV_H. This method has a potential in providing the morphological and spectral characteristics evolution of the iAs-related cells or particles, revealing the actual risk of arsenic contamination and metabolism. [ABSTRACT FROM AUTHOR]

Comprehensive evaluation of through‐silicon via (TSV) reliability often requires deterministic and 3D descriptions of local morphological and statistical features of via formation with the Bosch process. Here, a highly sensitive phase‐contrast X‐ray microtomography approach is presented based on recorrection of abnormal projections, which provides comprehensive and quantitative characterization of TSV etching performance. The key idea is to replace the abnormal projections at specific angles in principles of linear interpolation of neighboring projections, and to distinguish the interface between silicon and air by using phase‐retrieval algorithms. It is demonstrated that such a scheme achieves high accuracy in obtaining the etch profile based on the 3D microstructure of the vias, including diameter, bottom curvature radius, depth and sidewall angle. More importantly, the 3D profile error of the via sidewall and the consistency of parameters among all the vias are achieved and analyzed statistically. The datasets in the results and the 3D microstructure can be applied directly to a reference and model for further finite element analysis. This method is general and has potentially broad applications in 3D integrated circuits. [ABSTRACT FROM AUTHOR]

Synchrotron‐based X‐ray phase sensitive micro‐tomography techniques enable to visualize detailed three‐dimensional (3D) insight into nondestructive inner‐structure of biomedical samples. Different phase sensitive mechanisms have been employed for discrimination of tissue's tiny density variations in biomedical research. We effectively visualized and analyzed the phase‐contrast experimental results of X‐ray grating‐based imaging, based on grating interferometry with phase stepping, by using transgenic mouse fetus. We quantitatively measured and evaluated the contrast‐to‐noise ratio or the mass density resolution, spatial resolution, radiation dose, and figure of merit of X‐ray grating‐based imaging technique in biomedical research respectively. Moreover, the complex coherent degrees of light source were duly taken into account in the analysis of spatial resolution. In addition, the mass density distribution of soft biomedical specimens can be estimated using our presented method preliminarily. For most soft tissue and organ observation, this work provides explicit guidelines to help future synchrotron users obtain the quantitative image information, suitable for their specific biomedical research. [ABSTRACT FROM AUTHOR]

The quantification of micro-vasculatures is important for the analysis of angiogenesis on which the detection of tumor growth or hepatic fibrosis depends. Synchrotron-based X-ray computed micro-tomography (SR-µCT) allows rapid acquisition of micro-vasculature images at micrometer-scale spatial resolution. Through skeletonization, the statistical features of the micro-vasculature can be extracted from the skeleton of the micro-vasculatures. Thinning is a widely used algorithm to produce the vascular skeleton in medical research. Existing three-dimensional thinning methods normally emphasize the preservation of topological structure rather than geometrical features in generating the skeleton of a volumetric object. This results in three problems and limits the accuracy of the quantitative results related to the geometrical structure of the vasculature. The problems include the excessively shortened length of elongated objects, eliminated branches of blood vessel tree structure, and numerous noisy spurious branches. The inaccuracy of the skeleton directly introduces errors in the quantitative analysis, especially on the parameters concerning the vascular length and the counts of vessel segments and branching points. In this paper, a robust method using a consolidated end-point constraint for thinning, which generates geometry-preserving skeletons in addition to maintaining the topology of the vasculature, is presented. The improved skeleton can be used to produce more accurate quantitative results. Experimental results from high-resolution SR-µCT images show that the end-point constraint produced by the proposed method can significantly improve the accuracy of the skeleton obtained using the existing ITK three-dimensional thinning filter. The produced skeleton has laid the groundwork for accurate quantification of the angiogenesis. This is critical for the early detection of tumors and assessing anti-angiogenesis treatments. [ABSTRACT FROM AUTHOR]

Serenoa repens (saw palmetto) berries are one of the most consumed medicinal herbs in the United States and the wild green variety is used in the initial therapy of benign prostatic hyperplasia (BPH), globally. Use of saw palmetto is approved by the German Commission E, and several clinical trials are underway for evaluation of its efficacy. Exploitation of its habitats and over foraging imperil this plant, which only grows in the wild. This is the first study, to propose the use of the S. repens forma glauca (silver variety) as a qualitative substitute for the wild variety, to support its conservation. We compared tissue microstructures and lipid and water distribution through spatial imaging and examined metabolite distribution of three tissue domains and whole berries. This combined approach of 3D imaging and metabolomics provides a new strategy for studying phenotypic traits and metabolite synthesis of closely related plant varieties. [ABSTRACT FROM AUTHOR]