Study on the thermo-hydraulic behaviors of the new-pattern fuel assembly in lead-based fast reactors based on OpenFOAM

To improve the heat transfer efficiency of the coolant in lead-based fast reactors,this study optimized the configuration and rotational direction of the spacer wires in fuel assemblies to design a new-pattern fuel assembly.This study conducted detailed comparisons between traditional and new pattern fuel assembly rod bundles utilizing the open-source computational fluid dynamics platform,OpenFOAM.The results indicated that the new design may significantly reduce the pressure drop along the rod bundle,which is beneficial for lowering the pressure drop.Furthermore,this new design improved coolant mixing in the subchannels,which facilitated a more uniform temperature distribution and lower thermal gradients at the assembly outlet.These factors collectively reduced the thermal fatigue and creep in nearby internal components.Overall,the newpattern fuel assembly proposed in this study may have better heat transfer performance,thereby enhancing the Integrated Thermal-Hydraulic Factor by 48.2% compared to the traditional pattern.

Transcription factor Dmrt1 triggers the SPRY1-NF-κB pathway to maintain testicular immune homeostasis and male fertility

Bacterial or viral infections,such as Brucella,mumps virus,herpes simplex virus,and Zika virus,destroy immune homeostasis of the testes,leading to spermatogenesis disorder and infertility.Of note,recent research shows that SARS-CoV-2 can infect male gonads and destroy Sertoli and Leydig cells,leading to male reproductive dysfunction.Due to the many side effects associated with antibiotic therapy,finding alternative treatments for inflammatory injury remains critical.Here,we found that Dmrt1 plays an important role in regulating testicular immune homeostasis.Knockdown of Dmrt1 in male mice inhibited spermatogenesis with a broad inflammatory response in seminiferous tubules and led to the loss of spermatogenic epithelial cells.Chromatin immunoprecipitation sequencing(ChIP-seq)and RNA sequencing(RNA-seq)revealed that Dmrt1 positively regulated the expression of Spry1,an inhibitory protein of the receptor tyrosine kinase(RTK)signaling pathway.Furthermore,immunoprecipitation-mass spectrometry(IP-MS)and co-immunoprecipitation(Co-IP)analysis indicated that SPRY1 binds to nuclear factor kappa B1(NF-κB1)to prevent nuclear translocation of p65,inhibit activation of NF-κB signaling,prevent excessive inflammatory reaction in the testis,and protect the integrity of the blood-testis barrier.In view of this newly identified Dmrt1-Spry1-NF-κB axis mechanism in the regulation of testicular immune homeostasis,our study opens new avenues for the prevention and treatment of male reproductive diseases in humans and livestock.

Assessment of early factors for identification or prediction severe acute pancreatitis in pregnancy

BACKGROUND Acute pancreatitis in pregnancy(APIP)is a rare and serious condition,and severe APIP(SAPIP)can lead to pancreatic necrosis,abscess,multiple organ dysfunction,and other adverse maternal and infant outcomes.Therefore,early identification or prediction of SAPIP is important.AIM To assess factors for early identification or prediction of SAPIP.METHODS The clinical data of patients with APIP were retrospectively analyzed.Patients were classified with mild acute pancreatitis or severe acute pancreatitis,and the clinical characteristics and laboratory biochemical indexes were compared between the two groups.Logical regression and receiver operating characteristic curve analyses were performed to assess the efficacy of the factors for identification or prediction of SAPIP.RESULTS A total of 45 APIP patients were enrolled.Compared with the mild acute pancreatitis group,the severe acute pancreatitis group had significantly increased(P<0.01)heart rate(HR),hemoglobin,neutrophil ratio(NEUT%),and neutrophil–lymphocyte ratio(NLR),while lymphocytes were significantly decreased(P<0.01).Logical regression analysis showed that HR,NEUT%,NLR,and lymphocyte count differed significantly(P<0.01)between the groups.These may be factors for early identification or prediction of SAPIP.The area under the curve of HR,NEUT%,NLR,and lymphocyte count in the receiver operating characteristic curve analysis was 0.748,0.732,0.821,and 0.774,respectively.The combined analysis showed that the area under the curve,sensitivity,and specificity were 0.869,90.5%,and 70.8%,respectively.CONCLUSION HR,NEUT%,NLR,and lymphocyte count can be used for early identification or prediction of SAPIP,and the combination of the four factors is expected to improve identification or prediction of SAPIP.

OCT6 inhibits differentiation of porcine-induced pluripotent stem cells through MAPK and PI3K signaling regulation

As a transcription factor of the Pit-Oct-Unc(POU)domain family,octamer-binding transcription factor 6(OCT6)participates in various aspects of stem cell development and differentiation.At present,however,its role in porcine-induced pluripotent stem cells(piPSCs)remains unclear.Here,we explored the function of OCT6 in piPSCs.We found that piPSCs overexpressing OCT6 maintained colony morphology and pluripotency under differentiation conditions,with a similar gene expression pattern to that of non-differentiated piPSCs.Functional analysis revealed that OCT6 attenuated the adverse effects of extracellular signal-regulated kinase(ERK)signaling pathway inhibition on piPSC pluripotency by activating phosphatidylinositol 3-kinase-protein kinase B(PI3K-AKT)signaling activity.Our research sheds new light on the mechanism by which OCT6 promotes PSC maintenance.

CFD analysis of a CiADS fuel assembly during the steam generator tube rupture accident based on the LBEsteamEulerFoam

Steam generator tube rupture(SGTR) accident is an important scenario needed to be considered in the safety analysis of lead-based fast reactors. When the steam generator tube breaks close to the main pump, water vapor will enter the reactor core, resulting in a two-phase flow of heavy liquid metal and water vapor in fuel assemblies. The thermal-hydraulic problems caused by the SGTR accident may seriously threaten reactor core's safety performance. In this paper, the open-source CFD calculation software OpenFOAM was used to encapsulate the improved Euler method into the self-developed solver LBEsteamEulerFoam. By changing different heating boundary conditions and inlet coolant types, the two-phase flow in the fuel assembly with different inlet gas content was simulated under various accident conditions. The calculation results show that the water vapor may accumulate in edge and corner channels. With the increase in inlet water vapor content, outlet coolant velocity increases gradually. When the inlet water vapor content is more than 15%, the outlet coolant temperature rises sharply with strong temperature fluctuation. When the inlet water vapor content is in the range of 5–20%, the upper part of the fuel assembly will gradually accumulate to form large bubbles. Compared with the VOF method, Euler method has higher computational efficiency. However, Euler method may cause an underestimation of the void fraction, so it still needs to be calibrated with future experimental data of the two-phase flow in fuel assembly.

Perioperative restricted fluid therapy preserves immunological function in patients with colorectal cancer

AIM: To investigate the effect of perioperative restricted fluid therapy on circulating CD4+/CD8+ T lymphocyte ratio, percentage of regulatory T cells (Treg) and postoperative complications in patients with colorectal cancer.

Bifurcation Problems for a Class of Degenerate Quasilinear Elliptic Equations

In this paper we consider the bifurcation problem -div A（x, u）=λa（x）｜u｜^p-2u＋f（x,u,λ） in Ω with p 〉 1.Under some proper assumptions on A（x,ξ）,a（x） and f（x,u,λ）,we show that the existence of an unbounded branch of positive solutions bifurcating Irom the principal eigenvalue of the problem --div A（x, u）=λa（x）｜u｜^p-2u.

绿药淫羊藿的花特征与传粉生物学研究

植物花部特征的表达和进化是对生长环境长期适应的结果,生长环境的不同虽然会导致花部特征出现显著的差异,但是并不影响花在植物繁殖方面发挥的作用。淫羊藿属(Epimedium)植物具有雌雄异位和雌雄异熟机制,能有效地避免自交现象的发生,而恶劣的生长环境是否会使自交不亲和性发生改变?本文以生长于夜雨频发和潮湿环境中的绿药淫羊藿(Epimedium chlorandrum)为研究对象,通过野外观察绿药淫羊藿的花部特征和访花者,测定花粉数、胚珠数、花粉活力、柱头可授性、花蜜量和糖浓度以及人工授粉实验等方法,探究绿药淫羊藿的花部特征对其生长环境的适应性,以及花在传粉和繁殖中发挥的作用。研究结果表明,绿药淫羊藿的花朵向地生长,内萼片和高度弯曲的距共同形成了一把保护伞,保护花药和柱头免受雨水的冲刷,同时防止花蜜被雨水稀释;绿药淫羊藿的访花者共有6种,以花蜜为食的三条熊蜂(Bombus trifasciatus)是唯一的有效传粉者,其传粉效率与花蜜的含糖量呈正相关关系;绿药淫羊藿的每朵花能够分泌花蜜约17.06±0.57μL,花蜜含糖量约为29.19±0.22 g/100 mL;花粉胚珠比约为7701.30±116.85,表明绿药淫羊藿的繁育系统为专性异交类型;人工异交授粉和人工自交授粉处理均能结出可育种子,表明绿药淫羊藿是自交亲和的。综上所述,绿药淫羊藿受到夜雨频发和传粉者短缺的生长环境限制,自交亲和机制在一定程度上能够缓解花粉短缺的限制。

Effect of Regulatory Network of Exosomes and microRNAs on Neurodegenerative Diseases

Objective： A comprehensive review of the network regulation of exosomes and microRNAs （miRNAs） in neurodegenerative diseases was done, centering on the mechanism of the formation of exosomes and miRNAs and the sorting mechanism of exosomal miRNAs, with the aim to provide a theoretical basis in the search of biomarkers and the treatment of neurodegenerative diseases. Data Sources： The comprehensive search used online literature databases including NCBI PubMed, Web of Science, Google Scholar, and Baidu Scholar. Study Selection- The study selection was based on the following keywords： exosomes, miRNAs, central nervous system （CNS）, and neurodegenerative diseases. The time limit for literature retrieval was from the year 2000 to 2018, with language restriction in English. Relevant articles were carefully reviewed, with no exclusions applied to study design and publication type. Results： Exosomes are the smallest nanoscale membranous microvesicles secreted by cells and contain important miRNAs, among other rich contents. In the CNS, exosomes can transport amyloid β-protein, α-synuclein, Huntington-associated protein 1, and superoxide dismutase I to other cells. These events relieve the abnormal accumulation of proteins and aggravating neurological diseases. In some neurodegenerative diseases including Alzheimer＇s disease, Parkinson＇s disease, Huntington＇s disease, and amyotrophic lateral sclerosis, miRNAs are pathologically altered as an inexorable course, suggesting that miRNAs may contribute neurodegeneration. Exosomes and miRNAs form a network to regulate the homeostasis of the CNS, both synergistically and individually. Conclusion： The network of exosomes and miRNAs that regulates CNS homeostasis is a promising biomarker for the diagnosis and treatment of neurodegenerative diseases.

Discovery of androecium color polymorphism in Epimedium pubescens with habitat preference of anther/pollen color in the genus

Aims Interspecific and intraspecific variation in flower color in natural populations provides an opportunity for us to understand the evolu-tion and maintenance of diversity of floral traits.Compared to cor-olla color,little is known about the color polymorphism of sexual organs in flowering plants.to explore evolutionary transitions of androecium color and polymorphism within species,interspecific and intraspecific variation in androecium(anther and pollen)color in the genus Epimedium(Berberidaceae)was investigated.Methods to explore the geographical patterns of anther/pollen color variation in Epimedium species,data of 45 species were collected and their phyl-ogeny was constructed based on available DNA sequences.to investi-gate whether intraspecific variation in androecium color relates to habitat preference,three environmental factors were measured in the field popu-lation of Epimedium pubescens in northeastern Sichuan,China,which plants had green or yellow androecia.Vegetative and reproductive traits of this species were compared between the two color morphs.Important Findings Androecium(anther and pollen)color polymorphism in field populations of Epimedium pubescens is reported here where nine populations are monomorphic with a green androecium but three populations are dimorphic with individuals having either a green or a yellow androecium.Inflorescence stalk height,stalk diameter,leaf number,flower number and spur length(as well as spur and nectar volume)were not significantly different between two morphs.Compared to the yellow morph,the green morph had relatively larger leaves and anthers,but smaller sepals.the green morph produced more pollen and larger seeds,but the same number of ovules.Seed set was not significantly different between green and yellow morph.Investigations of environmental factors in the color dimorphic popu-lations of E.pubescens indicated that the green morph was more likely to occur in habitats with relatively lower light intensity.the distribution survey of 45 Epimedium species showed that species with a green androecium tended to appear at lower elevations.Comparative phylogenetic analysis showed that transitions from yellow to a green androecium or to androecial color dimorphism occurred at least seven times.this genus,characterized by anther color diversity and containing some species with anther color polymorphism,provides a model system in which to study the evolution and maintenance of colorful sexual organs in flowering plants.