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In this study, we investigate the steam oxidation behaviors of molten zirconium alloy at exceptionally high temperatures of 1870 ℃ and 1970 ℃. A specialized high-temperature steam oxidation apparatus was established to conduct the steam oxidation experiment. The experiments yielded crucial data including oxidation weight gain results, macroscopic appearance of the oxide surface, and section morphology. Several new phenomena: α-Zr(O) precipitates and two-layer oxide structure, were observed in this study. Based on these observations, a complete mechanism of molten zirconium oxidation in steam was developed, providing an interpretive framework for the oxidation observed in this experiment. This newly proposed mechanism reevaluates the formation process of nonceramic precipitates in the molten bulk and its consequential impact on oxidation kinetics at temperatures below 2000 ℃. • High-temperature steam oxidation behaviors of molten zirconium alloy at 1870℃ and 1970℃ were studied. • The oxidation mechanism of molten zirconium was discussed. • The enhanced effect of the melt on the oxidation kinetics was analyzed. [ABSTRACT FROM AUTHOR]

With the development of sodium-cooled reactor (SFR), the research on the flow and heat transfer characteristics of liquid sodium becomes increasingly important and necessary. Through decades of experimental and theoretical research under different conditions, certain achievements have been obtained. To further carry out relevant studies, a review work on this topic is of necessity. As pointed out by scholars, sodium boiling might occur during hypothetical accidents, which might cause great damage to the SFRs. For safety analysis, the boiling of liquid sodium has already become a focus in this research area. Based on an extensive review on the published literature, this paper concerns two major topics, i.e. the boiling heat transfer and two-phase flow characteristics of liquid sodium. The former topic focuses on the characteristics of sodium boiling in pools, round tubes and annuli, including the correlations for the boiling heat transfer coefficient, the incipient boiling wall superheat and critical heat flux of dryout type. Also, the correlations for the single-phase flow in bundle channels are presented here due to the fact that relevant research on the sodium boiling in rod bundles is relatively insufficient and the relevant correlations are rarely found. For the part of two-phase flow characteristics, the correlations for the two-phase pressure drop multiplier are presented and analyzed. Finally, conclusions and prospects in this research field are summarized and proposed. [ABSTRACT FROM AUTHOR]

Due to the high-Rayleigh-number natural convection and strong turbulence in the volumetrically heated corium melt pools, it is difficult to capture the heat transfer characteristics in detail. The Large Eddy Simulation (LES) methods are more and more applicable to nuclear industry and have become powerful tools to analyze the complicated turbulent and multi-phase flows. In this paper, the Wall-Modeled LES (WMLES) method was employed for the simulation of three typical corium pool heat transfer experiments: BALI, LIVE and COPRA experiments. The melt pool temperature and heat flux from numerical simulations were in good comparison with experimental data. Then numerical simulation for the transient formation of two-layer corium pool was performed with prototypical corium to obtain the heat transfer data in reactor situation. There was a distinctive gap between the temperatures in two layers. The heat flux showed a decrease at the two-layer interface and a huge jump at the metal layer side. The thin metal layer on the top at the early stage of the two-layer formation will threaten the vessel integrity. [ABSTRACT FROM AUTHOR]

• A PARAFAC ratio ("PARIX") correlated with SUVA across diverse drinking waters • PARIX tracked the relative abundance of LC-OCD "building blocks" vs "humic substances" • PARIX indicated position on a gradient between aromatic vs degraded/weathered humics • PARIX predicted river water treatability by coagulation, ozonation and ion exchange • Further PARAFAC ratios indicated susceptibility to adsorption on powdered activated carbon Samples from fifty-five surface water resources and twenty-five drinking water treatment plants in Europe, Africa, Asia, and USA were used to analyse the fluorescence composition of global surface waters and predict aromaticity and treatability from fluorescence excitation emission matrices. Nine underlying fluorescence components were identified in the dataset using parallel factor analysis (PARAFAC) and differences in aromaticity and treatability could be predicted from ratios between components H ii (λ ex /λ em = 395/521), H iii (λ ex /λ em = 330/404), P i , (λ ex /λ em =290/365) and P ii (λ ex /λ em = 275/302). Component H ii tracked humic acids of primarily plant origin, H iii tracked weathered/oxidised humics and the "building block" fraction measured by LC-OCD, while P i and P ii tracked amino acids in the "low molecular weight neutrals" LC-OCD fraction. Ratios between PARAFAC components predicted DOC removal at lab scale for French rivers in standardized tests involving coagulation, powdered activated carbon (PAC), chlorination, ion exchange (IEX), and ozonation, alone and in combination. The ratio H ii /H iii , for convenience named "PARIX" standing for "PARAFAC index", predicted SUVA according to a simple relationship: SUVA = 4.0 x PARIX (RMSEp=0.55) Lmg−1m−1. These results expand the utility of fluorescence spectroscopy in water treatment applications, by demonstrating the existence of previously unknown relationships between fluorescence composition, aromaticity and treatability that appear to hold across diverse surface waters at various stages of drinking water treatment. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]

Abstract: The Wnt/β-catenin signaling pathway plays critical roles in self-renewal and differentiation of mesenchymal stem cells. However, very little is known about its role in the chondrogenesis of human adipose-derived stem cells (hADSCs). In this study, we analyzed protein expression of several key components of the Wnt/β-catenin signaling pathway using a 21-day in vitro model of hADSC chondrogenesis. Wnt1, β-catenin, and GSK3β levels increased sharply at day 12, peaked at day 18, and then declined. Expression of TCF1, a target gene of Wnt/β-catenin signaling, closely followed that of Wnt1. These results were consistent with changes in endonuclear β-catenin levels. Gene expression of the chondrocyte-specific markers, collagen type II (COL II), SOX9, and aggrecan, increased during hADSC chondrogenesis, peaked at day 12, and then declined. Adding a Wnt inhibitor (days 0–21) resulted in consistently elevated levels of COL II, SOX9, and aggrecan mRNA. In contrast, adding Wnt1 (days 0–21) to cultures led to sustained Wnt/β-catenin signaling over the 21 days and suppressed expression of chondrocyte-specific markers. Moreover, adding Wnt1 at late stages of differentiation (day 18) further diminished chondrocyte-specific marker expression. Together, these results showed that inactivation of Wnt/β-catenin signaling is needed for the progression of chondrogenesis and the maturation and phenotype maintenance of chondroid cells. [Copyright &y& Elsevier]

Abstract: Wnt/β-catenin signaling (WNT) has widespread roles during stem cell differentiation. Whether WNT suppresses or promotes insulin-producing cell (IPC) differentiation and function is still not known. In this study, we investigated the role of WNT signaling during human adipose-derived stem cell (hADSC) differentiation into IPCs. Western blot analysis revealed that several key components of WNT were dynamically regulated in a 12-day IPC differentiation assay. Specifically, protein levels of Wnt1, β-catenin, and GSK3β steadily increased from day 0 to day 9 and rapidly decreased by day 12 of differentiation. Similarly, endonuclear β-catenin levels peaked at day 9 and then, fell to pre-differentiation levels. The expression of two WNT pathway targets, TCF-1 and cyclin D1, closely followed the same pattern of regulation, confirming that WNT signaling was transiently activated during IPC differentiation. Interestingly, the inhibition of WNT signaling did not block IPC differentiation; instead, it resulted in the upregulation of IPC-specific markers, including PDX-1, insulin, IRS-1, and IRS-2. Notably, another IPC marker, glucokinase, remained downregulated since it is a direct target of WNT signaling. Next, we examined the effect of maintaining active WNT signaling from day 9 to day 12 of IPC differentiation. Differentiating cells were treated with Wnt1 on day 9, when WNT signaling is typically turned off, and subjected to gene expression analysis on day 12. Remarkably, Wnt1 treatment resulted in reduced expression of IPC-specific markers. Taken together, these data indicate that WNT may not be necessary for IPC differentiation but may be involved in IPC maturation. [Copyright &y& Elsevier]

• An ocean condition available analysis code based on RELAP5 MOD3.3 is developed. • Effects of single heaving and single rolling motion on OFNP under SBO were discussed. • Effects of combined motion of heaving and rolling on OFNP under SBO were discussed. In view of the safety characteristics of the offshore floating nuclear plant (OFNP), an ocean condition available analysis code based on RELAP5 MOD3.3 is developed and the influences of single heaving, single rolling and combined motion of heaving and rolling on a OFNP were analyzed under station blackout accident (SBO). The results indicate that heaving motion accelerates the drop in the reactor pressure. The flow fluctuation caused by heaving motion promoted the derivation of residual heat after SBO; Rolling motion accelerates the declination of the reactor pressures and the coolant temperature after SBO, and also causes a large flow oscillation in pipes. The results also shows that the combined motion is more severe than these two single conditions. The parameters variation under the combined motion is more similar to that under its rolling condition. The residual heat can be removed effectively under all these conditions and the security will not be threatened. [ABSTRACT FROM AUTHOR]

The relocation mechanisms of molten core have an important effect on the core degradation process which is a complicated coupled process of oxidation, flow, and heat transfer with great uncertainty. However, most relocation experiments are complicated integral-effects bundle experiments, too many factors are involved, and it is difficult to obtain the flow resistance correlation for the molten pool flow in the bundle channel. So in this paper, a separate-effects visualization experiment study on the flow mechanism of the molten pool relocation was conducted by using glycerol-water solutions at room temperature with a 2 × 2 bundle channel. The flow front of glycerol-water solutions can be captured by the high-speed camera via a transparent plexiglass shroud. And a new flow resistance correlation of the bundle channel for the molten pool relocation is obtained. In addition, the influence of flowing gas on the relocation process of the molten pool is also investigated. This study is supposed to provide valuable references for the calculation model of the molten pool relocation in severe accident analysis codes. • A separate-effects visualization experiment study on the flow mechanism of the molten pool relocation was conducted in room temperature. • A new flow resistance correlation of the bundle channel for the molten pool relocation is obtained. • The influence of flowing gas on the relocation process of the molten pool is investigated. [ABSTRACT FROM AUTHOR]

Some anti-cancer drugs have poor solubility and availability, and are easily eliminated by rapid metabolism in vivo. To fix the drugs at the administration site and delay their release, a release platform with multi-level and multi-function was designed. The results showed that the curcumin (Cur) loaded liposomes (Cur@Lip) were coated sequentially with positive Chitooligosaccharides (Cur@Lip-Cos) and negative phospholipids (Cur@Lip-Cos-PC), to enhance water solubility, encapsulation efficiency, and delayed the release of the Cur, stability and cell intake of the liposomes, and the bioactivity of the system. The Cur@Lip-Cos could significantly enhance the inhibitory effect of MCF-7, better than the Cur@Lip-Cos-PC. The Lips were then fixed in an injectable thiolated chitosan hydrogel for local immobilization and sustained release which can effectively delay the release of Cur to inhibit MCF-7 growth. In summary, the innovative and biomimetic liposomal hydrogels are expected to provide more ideas for the design of drug carriers. [Display omitted] • Biomimetic liposomes can be coated with chitooligosaccharides and phospholipids. • Curcumin-loaded liposomes coated with chitooligosaccharides can enhance the anti-tumor effect. • The innovative and biomimetic liposomal hydrogels can be injected and delay the release of curcumin. [ABSTRACT FROM AUTHOR]

Single-phase liquid sodium as a kind of ideal coolant is widely applied in the fields of nuclear reactor engineering, aerospace, solar energy and industrial waste heat utilization, due to the good heat transfer and flow characteristics. Therefore, numerous studies have been carried out experimentally and theoretically to investigate the heat and mass transfer performance by using liquid sodium in past decades, and most of them are concentrated on the experimental results, mechanisms and models of heat transfer and flow of liquid sodium. However, no comprehensive review article concerns on the thermal hydraulic characteristics of single-phase for liquid sodium. Thus, in this study, an analytical overview on thermal hydraulic characteristics of single-phase for liquid sodium is presented, using widely scattered available information from existing literature. It can be taken into account as a quick reference guide to have an overview of the thermal hydraulic characteristics of single-phase for liquid sodium in different channel geometries (circular tube, annular tube and rod bundles etc.) under different conditions. [ABSTRACT FROM AUTHOR]

In-Vessel Retention (IVR) of molten corium is an important strategy for management of severe accidents adopted by some active service generation II plus reactors and advanced generation III reactors like AP1000, Hualong one and APR1400. One of the most important factors contributing to IVR analysis can be attributed to the characteristics of heat transfer in the molten pool in the lower head of reactor pressure vessel (RPV), which directly determines the heat load imposed on the vessel wall of the RPV lower head. Besides, IVR is also an important strategy for management of severe accidents of Ocean Floating Reactor (OFR), whose flow and heat transfer characteristics are influenced by the ocean motion conditions. However, since all previous molten pool experiments were conducted under static condition, characteristics of the heat transfer in the molten pool thus obtained may be different from those under ocean motion conditions, thus not applicable to the latter. To address this issue, in this study, an experimental system was established, which includes a two-layer molten pool test facility and a swing motion platform. Based upon the system, the effects of the swing angle and swing period on the characteristics of heat transfer in the two-layer melt pool were investigated. In addition, a scaling method was proposed to select simulant materials for the two-layer corium pool. Results of the experiment show that the swing period and angle have a significant effect on the temperature field of the molten pool and the rate of heat transfer. We thus suggest that, in future studies, new heat transfer correlations, models and IVR analysis method for ocean floating reactors should be researched and developed to evaluate the IVR design of ocean floating reactors, which is critical for management of severe accidents of the ocean floating reactors. • Establishing a two-layer melt pool test facility with swing motion condition. • Scaling analysis was conducted to select simulant material for two-layer corium pool. • Investigating effects of swing angle and period on heat transfer characteristics of melt pool. • Temperature stratification in the molten pool decreases with the decrease of the swing period. • Peak value of average cooling power ratio increases with the decrease of swing period. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the frequently occurring malignant tumors in the world. Breast resection, high tumor recurrence rate and high dose chemotherapy cause great pain to patients. Is there a way to prevent tumor recurrence efficiently while promoting new tissue generation after tumor resection? Based on this, an injectable biocompatible thiolated chitosan (CSSH) hydrogel with pH-response was designed to be used for accurate treatment of tumor cells in the initial stage of tissue resection and for tissue reconstruction later. To improve the mechanical strength of hydrogels, reduce the toxic and side effects, and delay the release of doxorubicin (DOX), halloysite nanotubes (HNTs) were modified to obtain thiolated HNTs (HNTs-SH), then loaded DOX (DOX@HNTs-SH), and further cross-linked CSSH to form DOX@CSSH/HNTs-SH Gel. The results showed that HNTs-SH can be evenly dispersed in the gel matrix, which improve the compressive strength of the hydrogels. In vitro DOX release experiments showed that the hydrogels were pH sensitive, DOX released slowly at normal physiological pH, but released quickly in the acidic microenvironment of tumors. Cell experiments showed that DOX@CSSH/HNTs-SH Gel released DOX can be taken up by MCF-7, thereby effectively inhibited its growth. In vivo recurrence experiments showed that the carriers can reduce the toxic and side effects of DOX, and effectively inhibited the recurrence and repair the defect tissue after tumor resection. Therefore, the drug-loaded gel is expected to be used as a carrier for local accurate and effective drug release, especially for inhibiting recurrence and repairing defective tissues after tumor resection. [Display omitted] • The gels have thermosensitivity, injectability and good mechanical properties as slow and controlled release drug carriers. • The gels have good biocompatibility, and exert excellent tumoricidal effect in vitro and in vivo after loading doxorubicin. • The hydrogels can prevent tumor recurrence efficiently while promoting new tissue generation after tumor resection. [ABSTRACT FROM AUTHOR]

• A molten corium-concrete interaction (MCCI) analysis code MOQUICO is developed. • The code is validated using various experiments. • The MCCI analysis for light water reactor plants is performed using the developed code. After the Fukushima nuclear accident, great attention is being paid to the late-phase behavior of the severe accident in the reactor, especially the molten corium-concrete interaction (MCCI). The MCCI process is very complex, involving physical and chemical reactions, heat and mass transfer processes. Many factors will affect the final result, with a high degree of uncertainty and there are still many unknowns based on current knowledge. In this paper, aimed at the MCCI phenomena in the containment cavity during a hypothetical accident in the nuclear power plant, an MCCI analysis code MOQUICO was developed by coupling the models of molten corium-concrete heat transfer, the concrete pyrolysis, and the corium cooling characteristics. The code MOQUICO was validated using the CCI-2, CCI-3 and SURC-2 tests with limestone-common sand concrete (LCS), siliceous concrete (SIL), and basaltic concrete (BAS), respectively. The simulant axial and radial ablation depths, upward heat flux and melt temperature agreed well with the experimental measurements. Afterwards, the code was used to simulate the typical PWR and BWR nuclear power plants. The ablation depth and gas production were analyzed for both simulations. Furthermore, the corium cooling was studied with eight different water injection moments for PWR and sensitivity analysis for decay heat and concrete type was conducted for BWR. The analysis proved that the developed code is capable of simulating MCCI and related phenomena of Light Water Reactor (LWR). [ABSTRACT FROM AUTHOR]