A Deep Learning Model for Automatically Quantifying the Anterior Segment in Ultrasound Biomicroscopy Images of Implantable Collamer Lens Candidates.

OBJECTIVE: This study aimed to develop and evaluate a deep learning-based model that could automatically measure anterior segment (AS) parameters on preoperative ultrasound biomicroscopy (UBM) images of implantable Collamer lens (ICL) surgery candidates. METHODS: A total of 1164 panoramic UBM images were preoperatively obtained from 321 patients who received ICL surgery in the Eye Center of Renmin Hospital of Wuhan University (Wuhan, China) to develop an imaging database. First, the UNet++ network was utilized to segment AS tissues automatically, such as corneal lens and iris. In addition, image processing techniques and geometric localization algorithms were developed to automatically identify the anatomical landmarks (ALs) of pupil diameter (PD), anterior chamber depth (ACD), angle-to-angle distance (ATA), and sulcus-to-sulcus distance (STS). Based on the results of the latter two processes, PD, ACD, ATA, and STS can be measured. Meanwhile, an external dataset of 294 images from Huangshi Aier Eye Hospital was employed to further assess the model's performance in other center. Lastly, a subset of 100 random images from the external test set was chosen to compare the performance of the model with senior experts. RESULTS: Whether in the internal test dataset or external test dataset, using manual labeling as the reference standard, the models achieved a mean Dice coefficient exceeding 0.880. Additionally, the intra-class correlation coefficients (ICCs) of ALs' coordinates were all greater than 0.947, and the percentage of Euclidean distance distribution of ALs within 250 µm was over 95.24%.While the ICCs for PD, ACD, ATA, and STS were greater than 0.957, furthermore, the average relative error (ARE) of PD, ACD, ATA, and STS were below 2.41%. In terms of human versus machine performance, the ICCs between the measurements performed by the model and those by senior experts were all greater than 0.931. CONCLUSION: A deep learning-based model could measure AS parameters using UBM images of ICL candidates, and exhibited a performance similar to that of a senior ophthalmologist.

Genetic characterizations of Cryptosporidium spp. from children with or without diarrhea in Wenzhou, China: high probability of zoonotic transmission.

BACKGROUND: Cryptosporidium is a highly pathogenic parasite responsible for diarrhea in children worldwide. Here, the epidemiological status and genetic characteristics of Cryptosporidium in children with or without diarrhea were investigated with tracking of potential sources in Wenzhou City, China. METHODS: A total of 1032 children were recruited, 684 of whom had diarrhea and 348 without, from Yuying Children's Hospital in Wenzhou, China. Samples of stool were collected from each participant, followed by extraction of DNA, genotyping, and molecular identification of Cryptosporidium species and subtypes. RESULTS: Twenty-two of the 1032 (2.1%) children were infected with Cryptosporidium spp. with 2.5% (17/684) and 1.4% (5/348) in diarrhoeic and asymptomatic children, respectively. Four Cryptosporidium species were identified, including C. parvum (68.2%; 15/22), C. felis (13.6%; 3/22), C. viatorum (9.1%; 2/22), and C. baileyi (9.1%; 2/22). Two C. parvum subtypes named IIdA19G1 (n = 14) and IInA10 (n = 1), and one each of C. felis (XIXa) and C. viatorum (XVaA3g) subtype was found as well. CONCLUSIONS: This is the first research that identified Cryptosporidium in children of Wenzhou, China, using PCR. Identification of zoonotic C. parvum, C. felis, C. viatorum, and their subtypes indicate potential cross-species transmission of Cryptosporidium between children and animals. Additionally, the presence of C. baileyi in children suggests that this species has a wider host range than previously believed and that it possesses the capacity to infect humans.

Inactivation of hydrogenase-3 leads to enhancement of 1,3-propanediol and 2,3-butanediol production by Klebsiella pneumoniae.

Klebsiella pneumoniae can use glucose or glycerol as carbon sources to produce 1,3-propanediol or 2,3-butanediol, respectively. In the metabolism of Klebsiella pneumoniae, hydrogenase-3 is responsible for H2 production from formic acid, but it is not directly related to the synthesis pathways for 1,3-propanediol and 2,3-butanediol. In the first part of this research, hycEFG, which encodes subunits of the enzyme hydrogenase-3, was knocked out, so K. pneumoniae ΔhycEFG lost the ability to produce H2 during cultivation using glycerol as a carbon source. As a consequence, the concentration of 1,3-propanediol increased and the substrate (glycerol) conversion ratio reached 0.587 mol/mol. Then, K. pneumoniae ΔldhAΔhycEFG was constructed to erase lactic acid synthesis which led to the further increase of 1,3-propanediol concentration. A substrate (glycerol) conversion ratio of 0.628 mol/mol in batch conditions was achieved, which was higher compared to the wild type strain (0.545 mol/mol). Furthermore, since adhE encodes an alcohol dehydrogenase that catalyzes ethanol production from acetaldehyde, K. pneumoniae ΔldhAΔadhEΔhycEFG was constructed to prevent ethanol production. Contrary to expectations, this did not lead to a further increase, but to a decrease in 1,3-propanediol production. In the second part of this research, glucose was used as the carbon source to produce 2,3-butanediol. Knocking out hycEFG had distinct positive effect on 2,3-butanediol production. Especially in K. pneumoniae ΔldhAΔadhEΔhycEFG, a substrate (glucose) conversion ratio of 0.730 mol/mol was reached, which is higher compared to wild type strain (0.504 mol/mol). This work suggests that the inactivation of hydrogenase-3 may have a global effect on the metabolic regulation of K. pneumoniae, leading to the improvement of the production of two industrially important bulk chemicals, 1,3-propanediol and 2,3-butanediol.

Correlation Between Anterior Chamber Angle Status and Limbal Stem Cell Deficiency in Primary Angle-Closure Glaucoma.

PURPOSE: To investigate the correlation between the opening and closing states of anterior chamber angle (ACA) and the density of limbal epithelial basal cells (LEBCs) in subjects with primary angle-closure glaucoma (PACG). DESIGN: Cross-sectional observational study. METHODS: A total of 54 eyes of 29 patients diagnosed with PACG were included in the study. Fifty-four eyes from normal subjects were included as control. Automatic evaluation system for ultrasound biomicroscopy images of anterior chamber angle was used to assist ophthalmologists in identifying the opening or closing state of ACA, and the in vivo confocal microscopy (IVCM) was used to evaluate the density of LEBCs in different directions. RESULTS: (1) The average density of LEBCs in the superior, inferior, nasal, and temporal limbus of the eyes in the PACG group was lower than that in the control group, and this pattern did not align with the density distribution observed in the control group. (2) In the early, moderate and advanced PACG, the density of LEBCs corresponding to the closed angle was lower than that in the control group (P < .05). Compared with the density of LEBCs corresponding to the closed angle and the open angle, the closed angle of PACG in the early, moderate and advanced stages was less than that in the open angle (P < .05 in the early and moderate stages; advanced stage P > .05). (3) The basal cell density was processed by dimensionless analysis. In the data calculated by averaging and minimizing, both closed angle dimensionless values were smaller than the open angle (P < .05). (4) Comparative analysis was conducted among the normal, open-angle, and closed-angle conditions in the superior, inferior, nasal, and temporal limbus. In the early stage of PACG, significant differences were observed in 4 limbal regions (P < .05), while in the moderate PACG stage, this difference was noted in 3 limbal regions (P < .05). In advanced PACG, 2 limbal regions exhibited significant differences (P < .05). These findings suggest that during the early PACG stage, angle closure is the predominant influencing factor on LEBCs density, while in the advanced stage, the decrease in density is attributed to a combination of angle closure and the natural progression of the disease. CONCLUSIONS: There is a significant correlation between anterior chamber angle status and LEBCs. Advanced PACG and angle closure should be highly suspected of the occurrence of limbal stem cell deficiency (LSCD).

Mapping stakeholders' relationships management in fulfilling corporate social responsibility: A study of China's construction industry.

Businesses today face a strong call for implementing corporate social responsibilities (CSR) subject to stakeholders' multiple expectations on the creation of long-term value. However, a vast majority of companies have struggled with the challenge of stakeholder management in CSR fulfillment, giving rise to a waste of enterprise resources. This study aims to map out stakeholders' relationships in CSR fulfillment to underscore stakeholder management. 253 CSR reports published by Chinese listed construction companies from 2010 to 2021 were collected and analyzed to map the stakeholders' relationships. The results show that construction companies usually stress the importance of corporate governance and workers interest, followed by construction quality and environmental preservation in implementing CSR. They adopt three types of stakeholder management approaches: coercive, cooperative, and coordinated approaches. The study presents the latest effort in managing stakeholders' relationships in the domain of CSR research. It favors construction firms to reconsider CSR activities from the stakeholder management perspective.

Identification and characterization of a novel 6'-N-aminoglycoside acetyltransferase AAC(6')-Va from a clinical isolate of Aeromonas hydrophila.

Background: Aeromonas species have been identified as agents responsible for various diseases in both humans and animals. Multidrug-resistant Aeromonas strains pose a significant public health threat due to their emergence and spread in clinical settings and the environment. The aim of this study was to determine a novel resistance mechanism against aminoglycoside antimicrobials in a clinical isolate. Methods: The function of aac(6')-Va was verified by gene cloning and antibiotic susceptibility tests. To explore the in vivo activity of the enzyme, recombinant proteins were expressed, and enzyme kinetics were tested. To determine the molecular background and mechanism of aac(6')-Va, whole-genome sequencing and bioinformatic analysis were performed. Results: The novel aminoglycoside N-acetyltransferase gene aac(6')-Va confers resistance to several aminoglycosides. Among the antimicrobials tested, ribostamycin showed the highest increase (128-fold) in the minimum inhibitory concentration (MIC) compared with the control strains. According to the MIC results of the cloned aac(6')-Va, AAC(6')-Va also showed the highest catalytic efficiency for ribostamycin [kcat/Km ratio = (3.35 ± 0.17) × 104 M-1 s-1]. Sharing the highest amino acid identity of 54.68% with AAC(6')-VaIc, the novel aminoglycoside N-acetyltransferase constituted a new branch of the AAC(6') family due to its different resistance profiles. The gene context of aac(6')-Va and its close relatives was conserved in the genomes of species of the genus Aeromonas. Conclusion: The novel resistance gene aac(6')-Va confers resistance to several aminoglycosides, especially ribostamycin. Our finding of a novel resistance gene in clinical A. hydrophila will help us develop more effective treatments for this pathogen's infections.

Deep Learning-Based Model for Automatic Assessment of Anterior Angle Chamber in Ultrasound Biomicroscopy.

OBJECTIVE: The goal of the work described here was to develop and assess a deep learning-based model that could automatically segment anterior chamber angle (ACA) tissues; classify iris curvature (I-Curv), iris root insertion (IRI), and angle closure (AC); automatically locate scleral spur; and measure ACA parameters in ultrasound biomicroscopy (UBM) images. METHODS: A total of 11,006 UBM images were obtained from 1538 patients with primary angle-closure glaucoma who were admitted to the Eye Center of Renmin Hospital of Wuhan University (Wuhan, China) to develop an imaging database. The UNet++ network was used to segment ACA tissues automatically. In addition, two support vector machine (SVM) algorithms were developed to classify I-Curv and AC, and a logistic regression (LR) algorithm was developed to classify IRI. Meanwhile, an algorithm was developed to automatically locate the scleral spur and measure ACA parameters. An external data set of 1,658 images from Huangshi Aier Eye Hospital was used to evaluate the performance of the model under different conditions. An additional 439 images were collected to compare the performance of the model with experts. RESULTS: The model achieved accuracies of 95.2%, 88.9% and 85.6% in classification of AC, I-Curv and IRI, respectively. Compared with ophthalmologists, the model achieved an accuracy of 0.765 in classifying AC, I-Curv and IRI, indicating that its high accuracy was as high as that of the ophthalmologists (p > 0.05). The average relative errors (AREs) of ACA parameters were smaller than 15% in the internal data sets. Intraclass correlation coefficients (ICCs) of all the angle-related parameters were greater than 0.911. ICC values of all iris thickness parameters were greater than 0.884. The accurate measurement of ACA parameters partly depended on accurate localization of the scleral spur (p < 0.001). CONCLUSION: The model could effectively and accurately evaluate the ACA automatically based on fully automated analysis of UBM images, and it can potentially be a promising tool to assist ophthalmologists. The present study suggested that the deep learning model can be extensively applied to the evaluation of ACA and AC-related biometric risk factors, and it may broaden the application of UBM imaging in the clinical research of primary angle-closure glaucoma.

Evaluation of a computer-aided diagnostic model for corneal diseases by analyzing in vivo confocal microscopy images.

Objective: In order to automatically and rapidly recognize the layers of corneal images using in vivo confocal microscopy (IVCM) and classify them into normal and abnormal images, a computer-aided diagnostic model was developed and tested based on deep learning to reduce physicians' workload. Methods: A total of 19,612 corneal images were retrospectively collected from 423 patients who underwent IVCM between January 2021 and August 2022 from Renmin Hospital of Wuhan University (Wuhan, China) and Zhongnan Hospital of Wuhan University (Wuhan, China). Images were then reviewed and categorized by three corneal specialists before training and testing the models, including the layer recognition model (epithelium, bowman's membrane, stroma, and endothelium) and diagnostic model, to identify the layers of corneal images and distinguish normal images from abnormal images. Totally, 580 database-independent IVCM images were used in a human-machine competition to assess the speed and accuracy of image recognition by 4 ophthalmologists and artificial intelligence (AI). To evaluate the efficacy of the model, 8 trainees were employed to recognize these 580 images both with and without model assistance, and the results of the two evaluations were analyzed to explore the effects of model assistance. Results: The accuracy of the model reached 0.914, 0.957, 0.967, and 0.950 for the recognition of 4 layers of epithelium, bowman's membrane, stroma, and endothelium in the internal test dataset, respectively, and it was 0.961, 0.932, 0.945, and 0.959 for the recognition of normal/abnormal images at each layer, respectively. In the external test dataset, the accuracy of the recognition of corneal layers was 0.960, 0.965, 0.966, and 0.964, respectively, and the accuracy of normal/abnormal image recognition was 0.983, 0.972, 0.940, and 0.982, respectively. In the human-machine competition, the model achieved an accuracy of 0.929, which was similar to that of specialists and higher than that of senior physicians, and the recognition speed was 237 times faster than that of specialists. With model assistance, the accuracy of trainees increased from 0.712 to 0.886. Conclusion: A computer-aided diagnostic model was developed for IVCM images based on deep learning, which rapidly recognized the layers of corneal images and classified them as normal and abnormal. This model can increase the efficacy of clinical diagnosis and assist physicians in training and learning for clinical purposes.

Oxygen removal and silicon recovery from polycrystalline silicon kerf loss by combining vacuum magnesium thermal reduction and hydrochloric acid leaching.

With the strengthened awareness of environmental protection and the growing interests of wastes recycling, silicon recovery from polycrystalline silicon kerf loss (PSKL) has drawn extensive attentions all over the world. In this paper, an efficient and environmental friendly approach for oxygen removal and silicon recovery from PSKL by combining vacuum magnesium thermal reduction (VMTR) and hydrochloric acid leaching was proposed. The effects of temperature, duration and particle size on the reduction of PSKL were investigated thoroughly. It is proved that the amorphous SiO2 in PSKL can be reduced by magnesium vapor at 923 K to generate MgO, and then the produced MgO can be dissolved by hydrochloric acid to eliminate the impurity oxygen. The oxygen removal fraction and the silicon recovery efficiency attained 98.43% and 94.46%, respectively, under the optimal conditions, indicating that a high efficiency recovery of silicon from PSKL was achieved. Compared to the existing PSKL deoxidation technologies, e.g., the high temperature process and the hydrofluoric acid leaching method, this method requires a relatively lower temperature and the waste acid can be easily recovered. Additionally, by taking into accounts the fact that the MgCl2 in leaching liquor can be recycled for cyclic utilization with a molten salt electrolysis method, it should be suggested that an efficient and environmental friendly process for PSKL recycling was obtained, which shows good prospects for commercial application.

Identification of a novel aminoglycoside O-nucleotidyltransferase AadA33 in Providencia vermicola.

A novel chromosome-encoded aminoglycoside O-nucleotidyltransferase AadA33 was identified in Providencia vermicola strain P13. The AadA33 shares the highest amino acid identity of 51.28% with the function characterized AadA31. Antibiotic susceptibility testing and enzyme kinetics analysis revealed that the function of AadA33 is to mediate spectinomycin and streptomycin resistance. The recombinant strain harboring aadA33 (pUCP20-aadA33/Escherichia coli DH5α) displayed >256- and 128-fold increases in the minimum inhibitory concentration levels to spectinomycin and streptomycin, respectively, compared with the control strains pUCP20/DH5α. Enzyme kinetic parameters manifested the substrate of AadA33 including spectinomycin and streptomycin, with k cat/K m of 3.28 × 104 (M-1 s-1) and 3.37 × 104 (M-1 s-1), respectively. Bioinformatics analysis revealed its structural mechanism of antimicrobial resistance, genetic context, and phylogenetic relationship with other aminoglycoside O-nucleotidyltransferases. This study of AadA33 contributed to understanding the function and resistance mechanism of aminoglycoside O-nucleotidyltransferase.

A new strategy for de-oxidation of diamond-wire sawing silicon waste via the synergistic effect of magnesium thermal reduction and hydrochloric acid leaching.

With the rapid development of photovoltaic industry, the amount of diamond-wire sawing silicon waste (DWSSW) increased dramatically. Recently, how to achieve cost-effective deoxygenation of DWSSW should be the most critical issue in silicon waste recycling. Herein, a new strategy for de-oxidation from DWSSW, employing Mg vapor as de-oxidation agent and hydrochloric acid (HCl) as leaching agent, under low temperature was suggested. The de-oxidation mechanism and the mineralogical evolution of different phases during the magnesium thermal reduction and acid leaching were clarified. Results showed that the impurity oxygen in DWSSW exists as amorphous SiO2 on the surface of Si particles, which can be eliminated by transforming it into crystalline MgO using magnesium thermal reduction and followed by acid leaching. As the reduction condition was controlled at 1333 K for 2 h, the residual oxygen content in DWSSW was 0.9643% and the de-oxidation fraction attained 93%. Additionally, the removal rate of impurities Al and Fe were 99.06% and 92.20%, respectively, and the Si recovery rate achieved 88%. Taking into consideration the recoverability of Mg, the cost of the process will be reduced significantly, making this process more viable in industry.

The roles of diol dehydratase from pdu operon on glycerol catabolism in Klebsiella pneumoniae.

The dha operon of Klebsiella pneumoniae is responsible for glycerol catabolism and 1,3-propanediol formation. Subunits of glycerol dehydratase and the large subunit of glycerol dehydratase reactivating factor are encoded by dhaBCE and dhaF, respectively. Proteins of pdu operon form a microcompartment (bacteria organelle) and responsible for 1,2-propanediol catabolism. In this operon, pduCDE and pduG encode subunits of diol dehydratase and its reactivating factor. Diol dehydratase is an isofunctional enzyme of glycerol dehydratase, but its role in glycerol catabolism was not entirely clear. In this study, dhaBCE, pduCDE, dhaF, and pduG in K. pneumoniae were knocked out individually or combinedly. These strains were cultured with glycerol as a substrate, and dehydratase activities in the cytoplasm and microcompartment were detected. Results showed that glycerol dehydratase and diol dehydratase were simultaneously responsible for glycerol catabolism in K. pneumoniae. Besides being packaged in microcompartment, large amounts of diol dehydratase was also presented in the cytoplasm. However, the Pdu microcompartment reduced the accumulation of 3-hydroxypropionaldehyde in the fermentation broth. PduG can cross reactivate glycerol dehydratase instead of DhaF. However, DhaF is not involved in reactivation of diol dehydratase. In conclusion, diol dehydratase and Pdu microcompartment play important roles in glycerol catabolism in K. pneumoniae.

Molten Salt Thermal Treatment Synthesis of S-Doped V2CTx and Its Performance as a Cathode in Aqueous Zn-Ion Batteries.

The lack of suitable cathode materials with a high capacity and good stability is a crucial problem affecting the development of aqueous Zn-ion batteries. Herein, a novel strategy for the modification of V2CTx through molten salt thermal treatment is proposed. In the novel route, S heteroatoms were introduced into V2CTx through a substitution reaction during the dissolution of Li2S in LiCl-KCl molten salts. Then, surface V2O5 was obtained through the in situ electrochemical charging/discharging of the S-doped V2CTx (MS-S-V2CTx) cathode. The assembled Zn/MS-S-V2CTx battery showed a high reversible discharge capacity of 411.3 mAh g-1 at a current density of 0.5 A g-1, an 80% capacitance retention after long cycle stability tests at 10 A g-1 for 3000 cycles, and a high energy density of 375.5 Wh kg-1 in 2M ZnSO4. Density functional theory calculations demonstrate that the improved electrochemical performance of the cathode can be attributed to the introduced S heteroatoms, which considerably reduced the ion diffusion energy barrier for Zn2+ ions and improved the stability of V2O5. This work provides a novel method to produce highly active and stable vanadium-based cathodes for aqueous Zn-ion batteries.

Blocking the 2,3-butanediol synthesis pathway of Klebsiella pneumoniae resulted in L-valine production.

Klebsiella pneumoniae is a 2,3-butanediol producing bacterium. Nevertheless, a design and construction of L-valine production strain was studied in this paper. The first step of 2,3-butanediol synthesis and branched-chain amino acid synthesis pathways share the same step of α-acetolactate synthesis from pyruvate. However, the two pathways are existing in parallel and do not interfere with each other in the wild-type strain. A knockout of budA blocked the 2,3-butanediol synthesis pathway and resulted in the L-valine production. The budA coded an α-acetolactate decarboxylase and catalyzed the acetoin formation from α-acetolactate. Furthermore, blocking the lactic acid synthesis by knocking out of ldhA, which is encoding a lactate dehydrogenase, improved the L-valine synthesis. 2-Ketoisovalerate is the precursor of L-valine, it is also an intermediate of the isobutanol synthesis pathway, while indole-3-pyruvate decarboxylase (ipdC) is responsible for isobutyraldehyde formation from 2-ketoisovalerate. Production of L-valine has been improved by knocking out of ipdC. On the other side, the ilvE, encoding a transaminase B, reversibly transfers one amino group from glutamate to α-ketoisovalerate. Overexpression of ilvE exhibited a distinct improvement of L-valine production. The brnQ encodes a branched-chain amino acid transporter, and L-valine production was further improved by disrupting brnQ. It is also revealed that weak acidic and aerobic conditions favor L-valine production. Based on these findings, L-valine production by metabolically engineered K. pneumonia was examined. In fed-batch fermentation, 22.4 g/L of L-valine was produced by the engineered K. pneumoniae ΔbudA-ΔldhA-ΔipdC-ΔbrnQ-ilvE after 55 h of cultivation, with a substrate conversion ratio of 0.27 mol/mol glucose.

Functional characterization of a novel aminoglycoside phosphotransferase, APH(9)-Ic, and its variant from Stenotrophomonas maltophilia.

Background: The intrinsic resistance mechanism plays an essential role in the bacterial resistance to a variety of the antimicrobials. The aim of this study is to find the chromosome-encoded novel antimicrobial resistance gene in the clinical isolate. Methods: The function of the predicted resistance gene was verified by gene cloning and antibiotic susceptibility test. Recombinant protein expression and enzyme kinetic studies were performed to explore the in vivo activity of the enzyme. Expression of the resistance gene exposed to antimicrobial was determined by RT-qPCR. Whole genome sequencing and bioinformatic analysis were applied to analyze the genetic context of the resistance gene. Results: The novel aminoglycoside (AG) resistance genes designated aph(9)-Ic and aph(9)-Ic1 confer resistance to spectinomycin, and a recombinant strain harboring aph(9)-Ic (pMD19-T-aph(9)-Ic/DH5α) showed a significantly increased minimum inhibitory concentration (MIC) level against spectinomycin compared with the control strains (DH5α and pMD19-T/DH5α). The result of the kinetic analysis of APH(9)-Ic was consistent with the MIC result for the recombinant pMD19-T-aph(9)-Ic/DH5α, showing the efficient catalytic activity for spectinomycin [kcat/Km ratio = (5.58 ± 0.31) × 104 M-1·s-1]. Whole-genome sequencing demonstrated that the aph(9)-Ic gene was located on the chromosome with a relatively conserved genetic environment, and no mobile genetic element was found in its surrounding region. Among all the function-characterized resistance genes, APH(9)-Ic shares the highest amino acid sequence identity of 33.75% with APH(9)-Ia. Conclusion: We characterized a novel AG resistance gene aph(9)-Ic and its variant aph(9)-Ic1 that mediated spectinomycin resistance from S. maltophilia. The identification of the novel AG resistance genes will assist us in elucidating the complexity of resistance mechanisms in microbial populations.

One-Pot Green Process to Synthesize MXene with Controllable Surface Terminations using Molten Salts.

Surface terminations of two-dimensional MXene (Ti3 C2 Tx ) considerably impact its physicochemical properties. Commonly used etching methods usually introduce -F surface terminations or metallic impurities in MXene. We present a new molten-salt-assisted electrochemical etching method to synthesize fluorine-free Ti3 C2 Cl2 . Using electrons as reaction agents, cathode reduction and anode etching can be spatially isolated; thus, no metallics are present in the Ti3 C2 Cl2 product. The surface terminations can be in situ modified from -Cl to -O and/or -S, which considerably shortens the modification steps and enriches the variety of surface terminations. The obtained -O-terminated Ti3 C2 Tx are excellent electrode materials for supercapacitors, exhibiting capacitances of 225 F g-1 at 1.0 Ag-1 , good rate performance (91.1 % at 10 Ag-1 ), and excellent capacitance retention (100 % after 10000 charge/discharge cycles at 10 Ag-1 ), which is superior to multi-layered Ti3 C2 Tx prepared by other etching methods.

Establishment of a Rat Model of Superior Sagittal-Sinus Occlusion via a Thread-Embolism Method.

The mechanisms contributing to the natural onset of cerebral venous sinus thrombosis (CVST) are mostly unknown, and a variety of uncontrollable factors are involved in the course of the disease, resulting in great limitations in clinical research. Therefore, the establishment of stable CVST animal models that can standardize a variety of uncontrollable confounding factors have helped to circumvent shortcomings in clinical research. In recent decades, a variety of CVST animal models have been constructed, but the results based on these models have been inconsistent and incomplete. Hence, in order to further explore the pathophysiological mechanisms of CVST, it is necessary to establish a novel and highly compatible animal model, which has important practical value and scientific significance for the diagnosis and treatment of CVST. In the present study, a novel Sprague-Dawley (SD) rat model of superior sagittal sinus (SSS) thrombosis was established via a thread-embolization method, and the stability and reliability of the model were verified. Additionally, we evaluated changes in cerebral venous blood flow in rats after the formation of CVST. Collectively, the SD-rat SSS-thrombosis model represents a novel CVST animal model that is easily established, minimizes trauma, yields good stability, and allows for accurately controlling ischemic timing and location.

Segregation and Morphological Evolution of Si Phase during Electromagnetic Directional Solidification of Hypereutectic Al-Si Alloys.

Understanding the Si segregation behavior in hypereutectic Al-Si alloys is important for controlling the micro- and macrostructures of ingots. The macrosegregation mechanism and morphological evolution of the primary Si phase were investigated during electromagnetic directional solidification (EMDS). Both numerical simulations and experimental results strongly suggested that the severe macrosegregation of the primary Si phase was caused by fluid flow and temperature distribution. Microscopic analysis showed that the morphological evolution of the Si crystal occurred as follows: planar → cellular → columnar → dendritic stages during EMDS. Based on constitutional supercooling theory, a predominance area diagram of Si morphology was established, indicating that the morphology could be precisely controlled by adjusting the values of temperature gradient (G), crystal growth rate (R), and solute concentration (C0). The results provide novel insight into controlling the morphologies of primary Si phases in hypereutectic Al-Si alloys and, simultaneously, strengthen our understanding of the macrosegregation mechanism in metallic alloys.

The Effect of Rod-Shaped Long-Period Stacking Ordered Phases Evolution on Corrosion Behavior of Mg95.33Zn2Y2.67 Alloy.

The morphology evolution of long-period stacking ordered (LPSO) phases on corrosion behavior of Mg95.33Zn2Y2.67 alloy is investigated systematically during as-cast, pre-extrusion heat-treated, as-extruded and post-extrusion heat-treated conditions. The second phases in the as-cast alloy are only LPSO phases with a few Y particles. The pre-extrusion heat treatment changed LPSO phases from blocks into a rudimentary rod shape with lamellar structure, subsequently into fine fragments by extrusion, and then into a regular rod shape with lamellar structure followed by post-extrusion heat treatment. Immersion tests and electrochemical measurements in 3.5 wt % NaCl solution reveal that the post-extrusion heat-treated alloy has the best corrosion resistance with the lowest corrosion rate. This is attributed to the rod-shaped LPSO phases, which could hinder corrosion proceeding, and result in corrosion orientated along the direction of rods and forming relatively dense long-strip corrosion products. Our findings demonstrate that the improved corrosion resistance of magnesium alloys with LPSO phases can be tailored effectively by the proceeding technology and post-heat treatment.