The miniaturization of nuclear reactor power is the direction of nuclear energy development in the future. A nuclear power system with a small solid core and cooled by a high-temperature alkali metal ...heat pipe has excellent safety performance. The start-up of the heat pipe cooled reactor depends on the heat pipe start-up characteristics from the frozen state, so transient analysis models of high-temperature heat pipe from the frozen state are established in this paper for the system characteristics analysis of the heat pipe cooled microreactor. The models include three stages of high-temperature heat pipe start-up from the frozen state: the molecular diffusion model of the free molecular stage, the flat-front model of the transitional flow process, and the 2-D thermal resistance network model of continuous flow. The energy conservation model is also used to consider the phase transition between solid, liquid, and gas. And The heat transfer limit model of heat pipe has been also coupled in the model. The models have been verified by the start-up experimental dates of the sodium heat pipe and the transient experimental dates of the water heat pipe. Then the models are applied to the system analysis code of the heat pipe reactor to analyze the transient experiment characteristics of a typical heat pipe reactor system. The results show that the predicted trend by HPMR system code is reasonable and the deviation with experimental data is less than 2%, which further demonstrates the applicability and effectiveness of the heat pipe transient models.
•A transient models of high temperature heat pipe from frozen state was established for the system analysis of HPMR.•The models include: the molecular diffusion model, the flat-front modeland the 2-D thermal resistance network model.•The models had been validated by the experimental dates of heat pipe andKURTY reactor test.
Coastal wetlands are highly heterogeneous due to their location between land and ocean. Clonal plants living in coastal wetlands can adapt to nutrient and salinity heterogeneity through clonal ...integration. However, little is known about how the single clonal ramet with fine roots adapts to nutrient heterogeneity within the microhabitat. Pot control experiments with 12 treatments were conducted to evaluate adaptive characteristics of
Phragmites australis
seedling to nutrient heterogeneity under salt stress. The results showed that under homogeneous nutrient treatment, 1.5% salt significantly reduced plant height and tiller number in
P. australis
and depressed the effect of nutrients on the leaf length, width and internode length. The homogeneous nutrient gradients had no significant effect on the aboveground biomass of
P. australis
in 1.5% salt condition. However, under 1.5% salt treatment, heterogeneous nutrient significantly reduced the underground biomass, including rhizome and adventitious root biomass. The root–shoot ratio was higher under homogeneous nutrient treatment than heterogeneous treatment with the same total nutrient amount applied. However, the accumulation of total nitrogen and total phosphorous in the stems and leaves of
P. australis
did not show significant differences, except that without salt stress, heterogeneous treatment decreased the total nitrogen content of stems and leaves at low nutrient levels. The results demonstrated a preference for homogeneous nutrient conditions in saline micro-environments in
P. australis
; however, when encountering heterogeneous soil nutrient environments, plants can maintain their nutrient requirements and even promote growth through physiological plasticity.
•Enterovirus 71 induces HMGB1 nucleocytoplasmic translocation and extracellular release.•Released HMGB1 exacerbates Enterovirus 71-induce Blood-Brain Barrier disruption.•Released HMGB1 enhances the ...phosphorylation of VE-cadherin at tyrosine 685, thereby destorying Blood-Brain Barrier intensity.
EV71 (Enterovirus 71) is a major causative agent of the outbreaks of HFMD (hand, foot, and mouth disease), which is associated with neurological damage caused by permeability disruption of BBB (blood-brain barrier). HMGB1 (high-mobility group box 1) is a widely expressed nuclear protein that triggers host inflammatory responses. Our work aimed to explore the function of HMGB1 in EV71 infection and its contributions to EV71-related BBB damage.
HeLa cells, HT-29 cells and AG6 mice were used to explore the translocation of HMGB1 in EV71 infection in vitro and in vivo. The roles of released HMGB1 on EV71 replication and associated inflammatory cytokines were investigated using recombinant HMGB1 in HeLa cells. The mechanisms of released HMGB1 in EV71-induced BBB injury were explored using recombinant HMGB1 and anti-HMGB1 neutralizing antibodies in monolayer HCMECs (immortalized human brain microvascular endothelial cells) and AG6 mice brain.
EV71 induced HMGB1 nucleocytoplasmic translocation and extracellular release in vitro and in vivo. Released HMGB1 acted as an inflammatory mediator in EV71 infection rather than affecting viral replication in vitro. Released HMGB1 disrupted BBB integrity by enhancing VE-cadherin phosphorylation at tyrosine 685 in HCMECs, and reducing total VE-cadherin levels in HCMECs and AG6 mice in EV71 infection. And released HMGB1 induced an increase in activated astrocytes. Neutralization of HMGB1 reversed the increased endothelial hyperpermeability and phosphorylation of VE-cadherin in HCMECs.
The inflammatory mediator HMGB1 released by EV71 exacerbated BBB disruption by enhancing VE-cadherin phosphorylation, which in turn aggravated EV71-induced neuroinflammation.
Display omitted
This study was designed to investigate the effect of the cortical cyclooxygenase-2 (COX2) pathway on depressive behaviour in rats. Meloxicam, COX2 overexpressed lentivirus and COX2 RNAi lentivirus ...were administered to Sprague-Dawley rats subjected to chronic unpredictable mild stress (CUMS). Behaviour tests, biochemistry and immunohistochemistry methods, enzyme-linked immunosorbent assays, western blotting and reverse transcription polymerase chain reactions were used to evaluate the changes in rat behaviour and the cortical COX2 pathway. CUMS rats showed depressive-like behaviours. The superoxide dismutase activity and cyclic adenosine monophosphate (cAMP) contents were significantly decreased, the contents of malondialdehyde, prostaglandin E2 (PGE2) and inflammatory cytokines were significantly increased. The expressions of protein kinase A (PKA) and cAMP response element-binding protein (CREB) were decreased, and the levels of brain-derived neurotrophic factor (BDNF) and COX2 were significantly increased. Meloxicam and COX2 RNAi lentivirus significantly alleviated the abnormalities induced by CUMS, while COX2 overexpressed lentivirus aggravated these abnormalities. Our results indicated that the cortical COX2 pathway was activated in CUMS rats. Inhibition of COX2 activity/expression can obviously improve depressive behaviours in CUMS rats. Upregulating COX2 expression can increase the susceptibility of rats to CUMS. An imbalance in the cortical COX2-PGE2-cAMP/PKA-CREB-BDNF signalling pathway participates in the pathogenic mechanism of depression.
Abstract Sclerostin monoclonal antibody (Scl-Ab) has been shown to increase bone mass and bone strength by stimulating bone formation in an ovariectomy-induced bone loss rat model. The purpose of ...this study was to determine the effects of Scl-Ab in a rat immobilization/disuse model in which there was both a decrease in bone formation and an increase in bone resorption. Ten-month-old female Sprague Dawley rats were divided into normal weight-bearing (normal-loaded, NL) and right hindlimb-immobilization (under-loaded, UL) groups. Both NL and UL rats were treated with vehicle or Scl-Ab at 5 or 25 mg/kg, twice per week for 4 weeks. Trabecular and cortical bone histomorphometric analyses were performed on the proximal tibial metaphysis (PTM) and tibial shaft (TS). Compared to NL controls, UL rats had reduced body and muscle weights, increased bone marrow fat cells in the PTM, increased trabecular bone resorption and periosteal mineral apposition rate (MAR) as well as decreased trabecular MAR and bone formation rate (BFR/BS). In NL bones, treatment with Scl-Ab significantly increased bone formation and decreased bone resorption, resulting in increased trabecular and cortical bone mass. In UL trabecular bone, treatment with Scl-Ab at 5 or 25 mg/kg induced significant and dose-dependent increases in trabecular bone volume and thickness, mineralized surfaces (MS/BS), MAR and BFR/BS, and a significant decrease in eroded surface (Er.S/BS) compared with UL controls. In UL cortical bone, Scl-Ab treatment induced significant increases in cortical width, periosteal and endocortical MS/BS, MAR and BFR/BS, and significant decreases in endocortical Er.S/BS compared with UL controls. Taken together, these findings suggest that antibody-mediated blockade of sclerostin represents a promising new therapeutic approach for the anabolic treatment of immobilization-induced osteopenia.
The purpose of this study was to explore the relationship between parenting styles and career decision-making difficulties in college students, and uncovered the mediating roles of core ...self-evaluation and career calling. A total of 1,127 undergraduates were recruited to complete the questionnaires about parenting styles, core self-evaluation, career calling, and career decision-making difficulties. The results showed that: (1) Positive and negative parenting styles could positively predict career decision-making difficulties in college students. (2) Core self-evaluation and career calling mediated the relationship between parenting styles and career decision-making difficulties. Sequential dual mediators only found in which positive paternal and maternal parenting styles predict career decision-making difficulties through core self-evaluation and career calling. (3) Further analysis revealed gender difference in the relationship between parenting styles and career decision-making difficulties. The relation between paternal positive parenting style and career decision-making difficulties was significant in male students, but absent in female students; the relation between maternal positive parenting and career decision-making difficulties and the relation between paternal negative parenting and career calling were significant in female students, but absent in male students; and the relation between career calling and career decision-making difficulties was greater in male than in female. The current study expanded and deepened those existing understandings about the relationship between parenting styles and adolescents’ career decisions, so as to further reveal its internal mechanism and provide more reasonable suggestions and targeted guidance for career counseling.
Mitogen-activated protein kinase (MAPK) pathways are major mediators of extracellular signals that are transduced to the nucleus. MAPK signaling is attenuated at several levels, and one class of ...dual-specificity phosphatases, the MAPK phosphatases (MKPs), inhibit MAPK signaling by dephosphorylating activated MAPKs. Several of the MKPs are themselves induced by the signaling pathways they regulate, forming negative feedback loops that attenuate the signals. We show here that in mouse embryos, Fibroblast growth factor receptors (FGFRs) are required for transcription of Dusp6, which encodes MKP3, an extracellular signal-regulated kinase (ERK)-specific MKP. Targeted inactivation of Dusp6 increases levels of phosphorylated ERK, as well as the pERK target, Erm, and transcripts initiated from the Dusp6 promoter itself. Finally, the Dusp6 mutant allele causes variably penetrant, dominant postnatal lethality, skeletal dwarfism, coronal craniosynostosis and hearing loss; phenotypes that are also characteristic of mutations that activate FGFRs inappropriately. Taken together, these results show that DUSP6 serves in vivo as a negative feedback regulator of FGFR signaling and suggest that mutations in DUSP6 or related genes are candidates for causing or modifying unexplained cases of FGFR-like syndromes.
This study aimed to discuss the role of 12/15-lipoxygenase (12/15-LOX) regulation involved in diabetes cognitive dysfunction. First, Mini Mental State Examination (MMSE) test was used to evaluate ...cognitive ability in diabetic patients and normal controls. The plasma test showed that the plasma level of 12/15-LOX in patients with MMSE scores below 27 was significantly increased compared with that of the normal group. Second, 12/15-LOX inhibitor was administered to diabetic rats. Behavioral tests, biochemistry, enzyme-linked immunosorbent assays, and Western blotting were used in this study. We found that the levels of fasting and random blood glucose increased rapidly in diabetic rats, the levels of triglycerides and total cholesterol in the diabetic group increased, and insulin levels decreased significantly. In the Morris water maze test, the escape latency was prolonged, and the crossing times decreased in the diabetic group. Under the microscope, the apoptosis of hippocampal neurons in diabetic rats increased significantly. The levels of TNF-α, IL-6 and 12-hydroxyindoleic acid (12(S)-HETE) significantly increased, and the protein expression of 12/15-LOX, p38 MAPK, Aβ1-42, caspase-3, caspase-9 and cPLA2 increased, while that of Bcl-2 decreased. However, the use of 12/15-LOX inhibitor reversed these results. Third, 12/15-LOX shRNA and p38MAPK inhibitor were administered to HT22 cells in high-glucose medium. The results of the cell experiment were consistent with those of the animal experiment. Our results indicated that the 12/15-LOX pathway participates in diabetic brain damage by activating p38MAPK to promote inflammation and neuronal apoptosis, and intervention 12/15-LOX can improve diabetic cognitive dysfunction.
Heat-pipe-cooled microreactors (HPMR) use a passive high-temperature alkali metal heat pipe to directly transfer the heat of solid core to the hot end of the intermediate heat exchanger or ...thermoelectric conversion device, thus avoiding a single point failure. To analyze and evaluate the transient safety characteristics of an HPMR system under accident conditions, such as heat pipe failure in the core or a loss of system heat sink and other accidents, a previously developed model for transient analysis of a heat-pipe-cooled space nuclear reactor power system (HPSR) was improved and validated in this study. The models improved mainly comprise: (1) An entire 2-D solid-core heat transfer model is established to analyze the accident conditions of core heat pipe failure and system heat sink loss. In this model, radial and axial Fourier heat conduction equations are used to divide the core into r-θ direction control volumes. The physical parameters of the material in the control volume are calculated according to the volume-weighted average. (2) By coupling the heat transfer limit model and the two-dimensional thermal resistance network model, the transient model of a heat pipe for HPMR system analysis is improved. (3) Conversion system models are established to simulate the system characteristics of the advanced HPMR concept, such as thermoelectric conversion, Stirling conversion, and the open Brayton conversion analysis model. Based on the improved models, the HPMR system analysis program TAPIRSD was developed, which was verified by experimental data of the separated conversion components and the ground nuclear test device KRUSTY. The maximum deviation of the power output predicted by the energy conversion model is less than 8%. The accident conditions of the KRUSTY tests, such as load change, core heat pipe failure, and heat sink loss accident, were studied by using TAPIRSD. The results show that the simulation results of the TAPIRSD code agree well with the experimental data of the KRUSTY prototype reactor. The maximum error between the TAPIRSD code prediction and the measured value of the core temperature under accident conditions is less than 10 K, and the maximum deviation is less than 2%. The results show that the developed code can predict the transient response process of the HPMR system well. At the same time, the accuracy and reliability of the improved model are proved. The TAPIRSD is suitable for system transient analysis of different types of HPMRs and provides an optional tool for the system safety characteristics analysis of HPMR.
Glucocorticoid (GC) induced osteoporosis (GIO) is caused by the long-term use of GC for treatment of autoimmune and inflammatory diseases. The GC related disruption of bone marrow microcirculation ...and increased adipogenesis contribute to GIO development. However, neither currently available anti-osteoporosis agent is completely addressed to microcirculation and bone marrow adipogenesis. Salvianolic acid B (Sal B) is a polyphenolic compound from a Chinese herbal medicine, Salvia miltiorrhiza Bunge. The aim of this study was to determine the effects of Sal B on osteoblast bone formation, angiogenesis and adipogenesis-associated GIO by performing marrow adipogenesis and microcirculation dilation and bone histomorphometry analyses. (1) In vivo study: Bone loss in GC treated rats was confirmed by significantly decreased BMD, bone strength, cancellous bone mass and architecture, osteoblast distribution, bone formation, marrow microvessel density and diameter along with down-regulation of marrow BMPs expression and increased adipogenesis. Daily treatment with Sal B (40 mg/kg/d) for 12 weeks in GC male rats prevented GC-induced cancellous bone loss and increased adipogenesis while increasing cancellous bone formation rate with improved local microcirculation by capillary dilation. Treatment with Sal B at a higher dose (80 mg/kg/d) not only prevented GC-induced osteopenia, but also increased cancellous bone mass and thickness, associated with increase of marrow BMPs expression, inhibited adipogenesis and further increased microvessel diameters. (2) In vitro study: In concentration from 10(-6) mol/L to 10(-7) mol/L, Sal B stimulated bone marrow stromal cell (MSC) differentiation to osteoblast and increased osteoblast activities, decreased GC associated adipogenic differentiation by down-regulation of PPARγ mRNA expression, increased Runx2 mRNA expression without osteoblast inducement, and, furthermore, Sal B decreased Dickkopf-1 and increased β-catenin mRNA expression with or without adipocyte inducement in MSC. We conclude that Sal B prevented bone loss in GC-treated rats through stimulation of osteogenesis, bone marrow angiogenesis and inhibition of adipogenesis.
PDF
