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ispartof: ISIJ INTERNATIONAL vol:62 issue:8 pages:1573-1585 status: published

ispartof: JOURNAL OF SUSTAINABLE METALLURGY vol:8 issue:1 pages:297-309 status: published

Calcium aluminate cement (CAC) was ground for 1 and 2 h to investigate the impact of mechanical grinding on CAC hydration at 30 °C and CAC-bonded castable strength. Phase composition and microstructure of unground and ground cements after hydration for predetermined times and terminated by the freeze-vacuum drying were compared. The results indicate that the particle size and particle size distribution of CAC were reduced and narrowed, respectively by grinding, thereby favoring the hydration rate and the conversation of C2AH8 to C3AH6. Then enhanced cement hydration also increases the strengths of castables bonded with milled CAC after drying and firing.

The conventional refractory sagger materials, e.g., mullite, cordierite, and magnesium aluminum spinel, employed to calcine Li-ion battery (LIB) cathode materials, are easily attacked by the LIB material and thus have short lifetimes. To improve the corrosion resistances of refractory saggers to LIB materials, andalusite–KAlSi2O6 (KAS4) materials with different contents of in-situ KAS4 were synthesized using andalusite and KAS4 precursor calcined at 1300 °C. The microstructure evolution, phase development, corrosion resistances to Li(NixCoyMnz)O2 (LNCM) cathode materials and thermomechanical properties of the designed andalusite-KAS4 materials were characterized. The results show that the corrosion resistances of the prepared andalusite–KAS4 material were superior to those of the LNCM materials owing to the in–situ KAS4 wrapping andalusite grains. The prepared andalusite–corundum–KAS4 materials also exhibited improved strengths and appropriate thermal shock resistances compared with mullite-based refractories.

BACKGROUND Circadian rhythm can modulate normal activity of humans in adapting to daily environment changes. Mechanical stress loading affects skeletal muscle development and bio-functions. This study aimed to investigate the effects of mechanical stress loading on circadian rhythm in skeletal muscle (C2C12 cells) and to explore the associated mechanism. MATERIAL AND METHODS C2C12 myoblasts were cultured and treated with mechanical stress loading. After mechanical stress loading for 6 h,12 h, and 24 h, we observed the C2C12 myoblasts and determined gene transcription and protein expression of Clock genes, including Clock, Bmal1, Per, and Cry using RT-PCR and western blot assay. RESULTS Mechanical stress loading triggered C2C12 cells growing by force direction and enhanced the cell proliferation at 6 h, 12 h, and 24 h. Gene transcription and protein expression of the core Clock-associated molecules, Clock and Bmal1, increased from start of loading to 12 h, and decreased from 12 h to 24 h. Gene transcription and protein expression of core Clock-associated molecules, Cry and Per, decreased in the first 12 h (from 6 h to 12 h) and increased in the last 12 h (from 12 h to 24 h). CONCLUSIONS Our study revealed that mechanical stress loading affected circadian rhythm in skeletal muscle (C2C12 myoblasts) through reducing Per/Cry and enhancing Clock/Bmal1 gene expression. This study provides insights for investigating circadian rhythm and associated bio-functions of humans.

Background Healthcare workers (HCWs) at the frontline are facing a substantial risk of infection during the coronavirus disease 2019 (COVID-19) outbreak. Methods We acquired information and data on general information on and infection and death status of HCWs in Wuhan during the COVID-19 outbreak and completed statistical analyses. Results We obtained the data on 2457 infected cases among HCWs in Wuhan, China. More than half of the infected individuals were nurses (52.06%), whereas 33.62% of infected cases were doctors and 14.33% of cases were medical staff. In particular, the case infection rate of nurses (2.22%) was remarkably higher than that of doctors (1.92%). Most infected cases among HCWs were female (72.28%). A majority of the infected HCWs (89.26%) came from general hospitals, followed by specialized hospitals (5.70%) and community hospitals (5.05%). The case infection rate of HCWs (2.10%) was dramatically higher than that of non-HCWs (0.43%). The case fatality rate of HCWs (0.69%) was significantly lower than that of non-HCWs (5.30%). Conclusions The infection risk of HCWs is clearly higher than that of non-HCWs. HCWs play an essential role in fighting the pandemic. The analysis of the infection status of HCWs is essential to attract enough attention from the public, provide effective suggestions for government agencies, and improve protective measures for HCWs.

Background: Recurrent aphthous stomatitis (RAS), a common oral mucosal disorder characterized by chronic, inflammatory, and ovoid ulcers, has a complex aetiology. The purpose of the study was to investigate the specific dietary factors influencing the prevalence of RAS.Methods: A total of 754 participants aged 18 to 59 years in Nanjing were enrolled in this descriptive cross-sectional study. An anonymous questionnaire was adopted to investigate the distribution of RAS, dietary factors, self-reported trigger factors, and therapeutic methods.Results: Among all participants, the prevalence rate of RAS was 21.4%. The univariable analysis suggested fruits, dairy products, vegetables, and drinking water, but not fried foods, fermented foods, spicy foods, and eggs, as preventive factors of RAS. After adjusting for age and sex, multivariable regression analysis suggested fruits (adjusted odds ratio [aOR] = .430, 95% confidence interval [CI] = [.218-.847], p = .015) and drinking water (aOR = .294, 95% CI = [.119-.726], p = .008) as protective factors of RAS. Conclusion: This study suggests that consumption of fruit and drinking water is negatively associated with RAS and dietary factors play an important role in RAS development. These results imply a potential adjunctive and complementary role of food in RAS treatment and some potential, simple, and feasible means for RAS prevention.

To deeply understand chemical interactions among nuclear materials during core meltdown, pre-oxidized Zircaloy-4 was re-heated under oxygen starvation to form thermodynamically stable ZrO2/α-Zr structure and then brought into contact with 316SS-B4C melt at 1300 °C. During re-heating, initial ZrO2 layer was partially dissolved due to thermodynamic instability, forming a new α-Zr layer at the external surface. Dissolution of ZrO2 layer could be linearly fitted with fourth root of re-heating time. When pre-oxidized and then re-heated Zircaloy-4 contacted with 316SS-B4C melt, the external α-Zr layer became oxygen-unsaturated and was dissolved first by 316SS-B4C melt. Initial ZrO2 layer was divided into two sublayers from the position where Zr5Sn3 phase was located. Due to direct contact with oxygen-unsaturated α-Zr layer, outer ZrO2 sublayer became thermodynamically unstable and was dissolved more rapidly than inner sublayer. The reaction zone consisting of multiple sublayers grew approximately linearly with time. Consequently, pre-oxidized and then re-heated Zircaloy-4 showed no significant improvement in delaying ZrO2 dissolution and reaction zone formation under the current experimental conditions, compared with only pre-oxidized Zircaloy-4.

During severe nuclear accidents, control rods rapidly liquefy at temperatures above 1250 °C due to eutectic reaction, forming a 304 stainless steel (304SS)-B4C melt. The melt will relocate and attack surrounding fuel rod claddings made of Zircaloy-4 (Zry-4). To understand to what extent ZrO2 oxide scale formed on Zry-4 will protect Zry-4 claddings against 304SS-B4C melt attack, we studied the chemical interactions between pre-oxidized Zry-4 and 304SS-B4C melt at 1300 °C. Bare Zry-4 was completely dissolved in 304SS-B4C melt within 60 min. The presence of ZrO2 oxide scale on Zry-4 significantly delayed the interactions, especially when ZrO2 oxide scale was dense. Typically, the reaction zone consists of ZrB2, Zr6(Fe,Ni,Cr)23 and Fe-Ni-Cr metallic phase at room temperature. Due to the presence of α-Zr and β-Zr in Zry-4 metal matrix, ZrO2 oxide scale becomes thermodynamically unstable. Dissolution of dense ZrO2 oxide scale can be described in three stages with different dissolution rates. Dissolution of ZrO2 oxide scale provides Zr source for the growth of reaction zone. Generally, the thickness of reaction zone linearly increases with time. Compared with the reaction couples of pre-oxidized Zry-4 and solid 316 stainless steel, both ZrO2 dissolution rate and reaction zone growth rate are much slower in the reaction couples of pre-oxidized Zry-4 and 304SS-B4C melt. The corresponding reasons were discussed.

The effect of nitrogen on the oxidation of Zr-1.7Sn-2.3Hf alloy in steam at 1200 °C was studied with respect to the oxidation kinetics and the underlying mechanism. Oxidation of Zr-1.7Sn-2.3Hf in steam obeys parabolic rate law regardless of the presence of nitrogen. Nitrogen, however, linearly accelerates the oxidation of Zr-1.7Sn-2.3Hf when its partial pressure exceeds a critical value. The accelerated oxidation of Zr-1.7Sn-2.3Hf is attributed to the cracks in the oxide layer caused by nitrogen. To account for the cracks, a new mechanism involving nucleation, growth and re-oxidation of ZrN precipitates was proposed.

Si-rich phases and their distributions in the oxide scale formed on 304 stainless steel (304SS) kinetically affects SiO2 volatilization for the formation of silicate-based Cs-bearing microparticles released during the Fukushima Daiichi Nuclear Power Plant accident. Therefore, we investigated Si-rich phases and their distributions in the oxide scale on 304SS oxidized in H2O–H2 mixtures over the temperature range 1000–1300 °C. SiO2 film stays at the base of the Cr2O3-type scale formed at low temperatures or high H2 contents in steam. Fe2SiO2 phase is non-uniformly distributed in the spinel-type scale formed under opposite conditions. Fe2SiO2 accumulation in the spinel-type scale is attributed to its thermodynamically metastable state in H2O–H2 mixtures. With increasing oxidation time, Fe2SiO2 phase was further oxidized into SiO2 phase.

The control blade and the fuel rod installed in channel box melt in steam during severe accident of a boiling water reactor. In order to clarify the melting phenomena and relocation of the structural material in the core of the reactor, interaction and melting behavior among B4C, 304 grade of stainless steel (SST), and Zircaloy-4 in atmosphere containing H2/H2O at 1473 K are investigated. The results showed that the reaction at the interface between B4C and SST under H2O atmosphere was slow and an oxidation was observed after 3600 s. Under H2O/H2 atmosphere, the concentration of B and C in the SST increased and the SST melted. Despite the atmosphere, an oxide layer formed on the surface of Zircaloy-4, and thus the reactions proceeded slowly when the Zircaloy-4 was contacted with B4C and SST. Under H2O atmosphere, continuous oxidation happened to SST, and SST was partially melted. Under H2 atmosphere, the SST was also melted due to the diffusion of B and C from the B4C. In addition, the oxidation o...

The effect of surfactant Te on the formation of MnS inclusions was studied by adding different amounts of Te to liquid steel at 1873 K (1600 °C). Coarse and fine MnS inclusions, which were formed, respectively, during and after solidification, were observed. Both types show a chain-like pattern, suggesting that they precipitate in the interdendritic regions. Te significantly decreases the area fraction of the coarse inclusions in the interdendritic regions. Moderate Te additions (25 and 50 ppm) make these inclusions more globular, whereas high Te addition (120 ppm) makes their surfaces rugged. Te also decreases the area fraction of the fine inclusions. High Te addition (120 ppm) modifies these inclusions from faceted to spherical, and makes them homogeneously distributed in the steel matrix. The suppressed precipitation of both coarse and fine MnS inclusions in the interdendritic regions suggests that Te alleviates S segregation. The mechanisms by which Te alleviates S segregation and modifies the morphology of MnS inclusions were discussed.

Herpes simplex virus type 1 (HSV1) is a complicated structural agent with a sophisticated transcription process and a high infection rate. A vaccine against HSV1 is urgently needed. As multiple viral-encoded proteins, including structural and nonstructural proteins, contribute to immune response stimulation, an attenuated or deficient HSV1 vaccine may be relatively reliable. Advances in genomic modification technologies provide reliable means of constructing various HSV vaccine candidates. Based on our previous work, an M6 mutant with mutations in the UL7, UL41, LAT, Us3, Us11 and Us12 genes was established. The mutant exhibited low proliferation in cells and an attenuated phenotype in an animal model. Furthermore, in mice and rhesus monkeys, the mutant can induce remarkable serum neutralizing antibody titers and T cell activation and protect against HSV1 challenge by impeding viral replication, dissemination and pathogenesis., Author summary Herpes simplex virus type 1 (HSV1) may lead to various herpes infections and can establish latent infection in neurons, which shows a high infectivity rate in populations. There is currently no effective therapeutic and prophylactic vaccine against HSV1. Previous studies have indicated that attenuated or deficient HSV1 vaccines are capable of safely eliciting a comprehensive protective immune response. With the advances in genomic modification technologies and accumulated knowledge of viral-encoded proteins, various predictable vaccine candidates can be reliably designed. In this work, a mutant M6 containing mutations in the UL7, UL41, LAT, Us3, Us11 and Us12 genes was established. Furthermore, the proliferation characteristics, virulence phenotype and immunogenicity of the mutant were analyzed in different cells and in mice and rhesus macaques.

Bone defects caused by many factors prompt further study of pathological process and restoration methods. This study was aimed to clarify the effect of erythropoietin on the repair of bone defect. We added the designated concentration of rhEPO to endothelial progenitor cells and marrow stromal cells, then detected its osteogenic and angiogenesis effects. The results showed that rhEPO promoted the proliferation of EPC and ST2 by promoting the mitosis without affecting cell apoptosis. The protein and mRNA levels of angiogenesis and osteogenic related factors exhibited higher expressions. Additionally, rhEPO encapsulated in PLGA scaffolds accelerated the new bone formation in rat calvaria bone defect model. Since the centre of bone defect was hypoxia environment, we cultured EPC and ST2 under hypoxia. SiRNA and an inhibitor of HIF-1 were used to interfere HIF-1, then the following changes of VEGF and EPO were detected. The results showed that all the factors were upregulated under the hypoxia environment. The expression of VEGF at protein and mRNA level decreased as HIF-1 was inhibited or interfered from 6 h, while the mRNA expression of EPO from 6 h and changed significantly at protein level from 12 h. Therefore, EPO is a promising factor for further studies.

This work aims at revealing the key factors that limit the cleaner production level of a pickling process. By comparing the difference in their characteristics and the corrosion behaviors in an acidic medium, three kinds of sample, including the matrix steel (AS), the naturally-corroded carbon steel (NR) and the carbon steel treated under high temperature oxidation (OR), after immersed in the experimental solutions with or without hexamethylenetetramine (HA), were characterized with the methods, such as, electrochemical polarization, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results indicated, no matter which kind of rust layers, the adsorption of HA on their surface all accorded with the same adsorption isotherm. Although the rust layers did not change the adsorption pattern of HA directly, but their steric effect would influence the adsorption potential of HA; the forming process of rust layers (under different environmental conditions) heavily influenced their composition, structure, and the interface roughness between the rust layer and the metal matrix, and also influenced the corrosion behavior of samples in an acidic medium, which were the key factors that limited the cleaner production level of a pickling process. These results indicated that an object-oriented pickling strategy should be adopted for a practical pickling process.

The effect of surfactant Te on the behavior of alumina inclusions at advancing solid-liquid interfaces of liquid steel was studied by adding Te to liquid steel before Al deoxidation at 1873 K. After water-quenching, the spatial distribution homogeneity of alumina inclusions in the steel matrix was characterized using the Dirichlet tessellation method. The deterioration of this homogeneity with increasing the addition of Te indicates that Te facilitates pushing of alumina inclusions. This phenomenon was discussed based on the thermodynamics of an asymmetric thin liquid film confined by an advancing solid-liquid interface and a particle. The surface excesses of Te at the solid-liquid and particle-liquid interfaces were theoretically demonstrated to decrease when an alumina inclusion moves towards the solid-liquid interface, thereby weakening the effect of Te on the solid-liquid and particle-liquid interfacial energies. Based on this, effect of surfactants was incorporated in the models predicting the critical velocity VC.

Surface active elements in liquid steel may affect the morphology of non-metallic particles during deoxidation. The effect of Te on the morphology of alumina particles was therefore studied by adding Te to molten iron before Al deoxidation at 1873 K. Dendritic, spherical, faceted, plate-like and clustered particles were identified in all samples. Te, however, considerably changes the rela-tive frequencies of the morphologies, decreasing the amount of dendritic and spherical particles whereas increasing the amount of faceted and plate-like particles. This effect is closely related with the supersaturation degree, stirring, and Te content. The way Te influences the morphology of the alumina particles and the factors influencing Te effectiveness are discussed. ispartof: ISIJ INTERNATIONAL vol:59 issue:9 pages:1529-1536 status: published

To investigate the densification of porous alumina plugs, hydrogen measurements, using the Hydris probe system, were performed in molten steel with different oxygen levels at around 1600 °C. The oxygen contents in molten steel were controlled by Al and Fe-Si alloy additions to 664, 296, 92, 51 and 2.5 ppm, respectively. High oxygen levels (> = 92 ppm) in molten steel were found to favor the infiltration of steel into porous alumina plug. The infiltrating steel interacts with SiO2-containing phases and Al2O3 inside the plug, forming liquid FeOnAl2O3-SiO2 slag and FeAl2O4 (hercynite). These newly formed phases, along with the infiltrating steel fill the porous structure of the alumina plugs. As a result, severe densification was observed inside the alumina plugs in contact with molten steel containing high oxygen levels. In comparison, no densification occurred in the plugs contacting with the steel having low oxygen contents of 51 and 2.5 ppm. ispartof: Journal of the European Ceramic Society vol:38 issue:6 pages:2662-2670 status: published

Autoimmune pancreatitis generally results in diffuse increased FDG activity throughout the pancreas on PET/CT images. We present a case of focal autoimmune pancreatitis with abnormal FDG activity involving only the pancreatic tail on PET/CT in a 61-year-old man who was provisionally diagnosed as having pancreatic cancer based on the CT findings. The diagnosis of autoimmune pancreatitis was based on pathological examination and elevated serum immunoglobulin G4 level. Following the steroid therapy, the patient was gradually recovered.

Electroslag casting with liquid metal (ESC LM) is a new technology in electroslag metallurgy. Solid ingot, hollow ingot and bimetal composite can be produced by the ESC LM process. Using both internal and external current carrying moulds for ESC LM is a new method for manufacturing hollow ingots. Liquid metal is employed directly during the ESC LM process rather than the conventional consumable electrode. The process was simulated using infinite element software ANSYS. The results indicate that the conductive path of the ESC LM process is entirely different from the conventional electroslag remelting process. There are two conductive current paths: one conductive path is transformer→external current conductive mould→liquid slag→internal current conductive mould→transformer, and another conductive path is transformer→external current conductive mould→liquid slag→molten steel pool→liquid slag→internal current conductive mould→transformer. Current density, magnetic inductive intensity, electromagneti...

Clustering of alumina inclusions during liquid processing of steel significantly influences its cleanliness and mechanical properties. We have therefore studied the effect of alumina inclusion morphology on their clustering behavior in molten iron. Alumina inclusions were extracted from iron samples taken at 1 min after Al addition. Dendritic, spherical, plate-like, faceted and clustered alumina inclusions were identified and their clustering degrees were measured. The clustering degree increases in the order of spherical, dendritic, plate-like and faceted inclusions. To explain this, attractive force between two alumina particles with different shape combinations, i.e., sphere-sphere (S-S), sphere-plane (S-P), plane-plane (P-P), was calculated based on the theory of spontaneous cavitation. The attractive force is influenced significantly by particle shape. S-S type has the smallest attractive force and the shortest acting length. P-P type has the largest attractive force and the longest acting length. This explains that spherical inclusions have the lowest clustering degree. The lower clustering degree of plate-like inclusions, compared with faceted inclusions, is due to that molten iron wets plate-like inclusions better. ispartof: ISIJ International vol:56 issue:6 pages:926-935 status: published

For the purpose of controlling the size of non-metallic inclusions in steel, the effect of interfacial properties of alumina inclusions and molten iron on the characteristics and clustering of alumina inclusions was investigated. The interfacial properties were modified by adding different amounts of Te to molten iron at 1873 K before Al deoxidization. When the melt is not stirred after Al addition, Te was found to decrease the size of alumina inclusions and to narrow the size distribution by promoting nucleation. This effect, however, fades out with increasing holding time. When the melt is stirred for 30 s after Al addition, Te favors alumina clustering. The mean diameter of alumina inclusions, the clustering degree and the average number of particles per cluster increase with increasing Te addition from 0 to 250 ppm, thereafter decrease with further Te addition. The effect of Te addition on the clustering of alumina inclusions is discussed from the viewpoint that Te makes alumina inclusions more faceted and Te decreases the surface tension of molten iron. ispartof: ISIJ International vol:55 issue:9 pages:1891-1900 status: published

© 2015 ISIJ. The alloy/liquid Fe interaction behaviour at early stages of deoxidation/alloying have considerable influence on the mechanical properties of steel products. The interfacial reaction between FeMnSi and liquid Fe, as well as the inclusion formation, were experimentally studied at the addition early stages based on quenched FeMnSi-Fe diffusion couples. The microstructure and composition of the quenched diffusion couple were evaluated and the inclusions in the reaction zone were characterised. Five regions were distinguished in the quenched reaction zone, i.e. (1) a solidified Fe shell, (2) a α1 phase consisting of a solid α1 phase and a Fe-Mn-Si liquid melt at the experimental temperature, (3) eutectic α1+Fe5Si3 and (4) eutectic Mn5Si3+MnSi phases, which are liquid at the experimental temperature and (5) the origina FeMnSi alloy which did not melt during the interaction. Plenty of oxysulphide inclusions are observed in the reaction zone: Fe(O,S) inclusions formed in the bulk iron and an inclusion poor zone is observed in the nner part of the Fe shell. Large amounts of tiny (Mn,Si)O inclusions formed in the α1 phase near the Fe/α1 interface and large (Mn,Si)(O,S) inclusions precipitated in the liquid phase after solidification. ispartof: ISIJ International vol:55 issue:8 pages:1661-1668 status: published

In this paper, the approaches of anti-fatigue design are briefly reviewed and are classified into three groups: nominal stress approach, local stress–strain approach and stress field intensity approach. Two types, each with two notches, are specially designed and a total of 30 specimens with 4 dimensions are tested under different constant–amplitude loading. These specimens are also analysed with elasto-plastic FEM to obtain stress–strain distributions and stress concentration factors. Fatigue life is estimated based on the different approaches. Experimental and analytical results show that the assumption of stress field intensity is more reasonable than that of the other approaches.

Particle-reinforced metal matrix composites (MMCs) have excellent physicochemical properties as structural materials. The morphology and distribution control of reinforcement particles during the fabrication of MMCs are difficult-but-critical-to-achieve required properties of the materials. This research demonstrates a possibility to quantitatively control the distribution of particles in the metal matrix by applying a magnetic field. A 2D numerical model is developed and applied to evaluate the behaviour of Fe-based metallic particles in aluminum MMCs. By combination of 2D simulation with intersectional directions, this model also provides some hints for 3D practice. The assembled structure is found to be governed by the external magnetic field orientation, magnetic flux density and magnetic susceptibility of the particles. Both behaviours of particle agglomeration and dispersion are quantitatively characterized in different conditions. By using a strong magnetic field, it is found that assembled structures of weakly magnetic particles can be effectively manipulated. Therefore, it can be expected to fabricate particle-enhanced metal matrix composites/ceramics/glass with substantial improvements in physical and chemical properties by using a magnetic field.