Interplay between topology and localization on superconducting circuits

Topological insulators occupy a prominent position in the realm of condensed matter physics. Nevertheless, the presence of strong disorder has the potential to disrupt the integrity of topological states, leading to the localization of all states.This study delves into the intricate interplay between topology and localization within the one-dimensional Su–Schrieffer–Heeger(SSH) model, which incorporates controllable off-diagonal quasi-periodic modulations on superconducting circuits.Through the application of external alternating current(ac) magnetic fluxes, each transmon undergoes controlled driving,enabling independent tuning of all coupling strengths. Within a framework of this model, we construct comprehensive phase diagrams delineating regions characterized by extended topologically nontrivial states, critical localization, and coexisting topological and critical localization phases. The paper also addresses the dynamics of qubit excitations, elucidating distinct quantum state transfers resulting from the intricate interplay between topology and localization. Additionally, we propose a method for detecting diverse quantum phases utilizing existing experimental setups.

miR-186-5p调控PRKAA2促进肺腺癌细胞铁死亡的机制研究

背景与目的肺腺癌是最常见的非小细胞肺癌组织学类型,miRNAs作为基因表达的调控分子调控细胞增殖、凋亡和分化,从而影响细胞内稳态。本研究通过实验验证miR-186-5p通过调控其下游靶蛋白PRKAA2影响铁死亡途径从而抑制肺腺癌细胞增殖、迁移和侵袭能力。方法前期研究获得肺癌中表达显著下调的miRNA,即miR-186-5p;生物信息学方法预测其下游铁死亡相关靶蛋白并查询其在肺腺癌中的表达水平及对患者生存预后的影响;双荧光素酶验证两者结合位点;实时荧光定量聚合酶链式反应(quantitative real-time polymerase chain reaction,qRT-PCR)和Western blot检测过表达miR-186-5p后PRKAA2的基因和蛋白表达情况;EdU、Transwell、划痕实验验证miR-186-5p在A549、H1299细胞中的增殖、侵袭迁移能力的影响以及miR-186-5p对Fer-1抑制铁死亡敏感性的作用机制;活性氧(reactive oxygen species,ROS)实验检测miR-186-5p对肺腺癌细胞ROS含量的影响;丙二醛(malondialdehyde,MDA)、谷胱甘肽(glutathione,GSH)实验检测miR-186-5p、PRKAA2对肺腺癌细胞铁死亡指标变化的影响;脂质ROS(lipid ROS,L-ROS)实验检测miR-186-5p、PRKAA2对肺腺癌细胞L-ROS含量的影响。结果PRKAA2在肺腺癌中表达上调;过表达miR-186-5p使PRKAA2的基因和蛋白表达量下降;过表达miR-186-5p通过调控PRA2促进铁死亡抑制肺腺癌细胞增殖、侵袭迁移能力;miR-186-5p能够增加A549细胞ROS含量;过表达miR-186-5p和敲低PRKAA2上调肺腺癌细胞MDA含量,下调还原型GSH含量;miR-186-5p通过靶向PRKAA2增加肺腺癌细胞L-ROS含量,促进肺腺癌细胞铁死亡敏感性。结论miR-186-5p通过靶向调控PRA2促进肺腺癌A549、H1299细胞铁死亡,从而抑制肺腺癌增殖、侵袭和迁移能力。

Searching for the Nano-Hertz Stochastic Gravitational Wave Background with the Chinese Pulsar Timing Array Data ReleaseⅠ

Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves(GWs).The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced pulsar-pairs.The Chinese Pulsar Timing Array(CPTA)is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio telescopes.This short article serves as a“table of contents”for a forthcoming series of papers related to the CPTA Data Release 1(CPTA DR1)which uses observations from the Five-hundred-meter Aperture Spherical radio Telescope.Here,after summarizing the time span and accuracy of CPTA DR1,we report the key results of our statistical inference finding a correlated signal with amplitude logA_(c)=-14.4_(-2.8)^(+1.0)for spectral index in the range ofα∈[-1.8,1.5]assuming a GW background(GWB)induced quadrupolar correlation.The search for the Hellings–Downs(HD)correlation curve is also presented,where some evidence for the HD correlation has been found that a 4.6σstatistical significance is achieved using the discrete frequency method around the frequency of 14 n Hz.We expect that the future International Pulsar Timing Array data analysis and the next CPTA data release will be more sensitive to the n Hz GWB,which could verify the current results.

Pickering乳液模板构建生物刺激响应性蛋白质微球

生物刺激响应性微球可用于封装活性物,并在生理条件刺激下触发释放活性物,在制药,化妆品,食品和农业等领域备受关注。然而大多数微球材料基于合成聚合物,合成过程中涉及的有机溶剂或交联剂残留易产生安全性与生物相容性隐患。因此,本工作以Pickering双重乳液为模板,探索一种简单、可持续地构建生物刺激响应性蛋白质微球的方法。具体地说,本文采用Stöber法合成了粒径约为100 nm的二氧化硅颗粒,并用二氯二甲基硅烷对其进行疏水改性。随后,Pickering双重乳液模板由疏水二氧化硅纳米颗粒稳定,玉米醇溶蛋白溶解在中间相。同时,乙醇的移除过程促使蛋白质析出并构成微球骨架。我们先通过染色法,分别用罗丹明B标记乙醇水相和芘标记油相,通过激光共聚焦(CLSM)证明了多重乳液的结构。并通过扫描电子显微镜(SEM)详细表征了蛋白微球和疏水二氧化硅颗粒的形貌,我们发现Pickering乳液模板制备的微球具有良好的球形度和均一性,且二氧化硅颗粒在微球表面均匀排列,其中疏水二氧化硅颗粒除了充当乳化剂外,还能提高蛋白微球的机械强度和单分散性。紧接着,我们以FITC标记的葡聚糖作为封装模型,通过CLSM证明了FITC-葡聚糖在蛋白微球中均匀分散且对微球结构没有影响。之后我们考察了蛋白微球的pH耐受性,通过光学显微镜发现,蛋白微球在pH 3–11条件下结构保持良好,只有在pH大于11的情况下才会分解释放,证明其具有良好的耐受性。最后,我们探索了蛋白微球的生物刺激响应行为,由于玉米醇溶蛋白含有大量的硫氨基酸,可形成分子内和分子间二硫键,而二硫键可以被谷胱甘肽(GSH)还原,且蛋白质本身具有酶解特性,因此该蛋白微球同时具有GSH和酶响应性,用荧光分光光度计测量了蛋白微球在不同GSH和酶浓度下FITC-葡聚糖的释放量,且由CLSM和SEM进一步验证了微球的分解行为。综上,Pickering乳液模板的良好稳定性和可调控性使蛋白质微球具有结构可控性。此外,结果显示该蛋白质微球对活性物有良好的保护与包封效果,且对蛋白酶和谷胱甘肽表现出非凡的生物刺激响应性。

Allocation patterns of nonstructural carbohydrates in response to CO_(2)elevation and nitrogen deposition in Cunninghamia lanceolata saplings

Stored nonstructural carbohydrates(NSC)indicate a balance between photosynthetic carbon(C)assimilation and growth investment or loss through respiration and root exudation.They play an important role in plant function and whole-plant level C cycling.CO_(2)elevation and nitrogen(N)deposition,which are two major environmental issues worldwide,aff ect plant photosynthetic C assimilation and C release in forest ecosystems.However,information regarding the eff ect of CO_(2)elevation and N deposition on NSC storage in diff erent organs remains limited,especially regarding the trade-off between growth and NSC reserves.Therefore,here we analyzed the variations in the NSC storage in diff erent organs of Chinese fi r(Cunninghamia lanceolata)under CO_(2)elevation and N addition and found that NSC concentrations and contents in all organs of Chinese fi r saplings increased remarkably under CO_(2)elevation.However,N addition induced diff erential accumulation of NSC among various organs.Specifi cally,N addition decreased the NSC concentrations of needles,branches,stems,and fi ne roots,but increased the NSC contents of branches and coarse roots.The increase in the NSC contents of roots was more pronounced than that in the NSC content of aboveground organs under CO_(2)elevation.The role of N addition in the increase in the structural biomass of aboveground organs was greater than that in the increase in the structural biomass of roots.This result indicated that a diff erent tradeoff between growth and NSC storage occurred to alleviate resource limitations under CO_(2)elevation and N addition and highlights the importance of separating biomass into structural biomass and NSC reserves when investigating the eff ects of environmental change on biomass allocation.

Pairing effects on the fragment mass distribution of Th,U,Pu,and Cm isotopes

In this article,a comprehensive study of the fission process of Th,U,Pu,and Cm isotopes using a Yukawa-folded meanfield plus standard pairing model is presented.The study focused on analyzing the effects of the pairing interaction on the fragment mass distribution and its dependence on nuclear elongation.The significant role of pairing interactions in the fragment mass distributions of^(230)Th,^(234)U,^(240)Pu,and^(246)Cm was demonstrated.Numerical analysis revealed that increasing the pairing interaction strength decreased the asymmetric fragment mass distribution and increased the symmetric distribution.Furthermore,the odd-even mass differences at symmetric and asymmetric fission points were examined,highlighting their sensitivity to changes in the pairing interaction strength.Systematic analysis of the Th,U,Pu,and Cm isotope fragment mass distributions demonstrated the effectiveness of the model in reproducing the experimental data.In addition,the effects of the zero-point energy and half-width parameter on the fragment mass distribution for^(240)Pu were explored.Thus,this study provides valuable insights into the fission process by emphasizing the importance of pairing interactions and their relationship with nuclear elongation.

Integrated analysis of single-cell and bulk RNA-seq establishes a novel signature for prediction in gastric cancer

BACKGROUND Single-cell sequencing technology provides the capability to analyze changes in specific cell types during the progression of disease.However,previous single-cell sequencing studies on gastric cancer(GC)have largely focused on immune cells and stromal cells,and further elucidation is required regarding the alterations that occur in gastric epithelial cells during the development of GC.AIM To create a GC prediction model based on single-cell and bulk RNA sequencing(bulk RNA-seq)data.METHODS In this study,we conducted a comprehensive analysis by integrating three singlecell RNA sequencing(scRNA-seq)datasets and ten bulk RNA-seq datasets.Our analysis mainly focused on determining cell proportions and identifying differentially expressed genes(DEGs).Specifically,we performed differential expression analysis among epithelial cells in GC tissues and normal gastric tissues(NAGs)and utilized both single-cell and bulk RNA-seq data to establish a prediction model for GC.We further validated the accuracy of the GC prediction model in bulk RNA-seq data.We also used Kaplan–Meier plots to verify the correlation between genes in the prediction model and the prognosis of GC.RESULTS By analyzing scRNA-seq data from a total of 70707 cells from GC tissue,NAG,and chronic gastric tissue,10 cell types were identified,and DEGs in GC and normal epithelial cells were screened.After determining the DEGs in GC and normal gastric samples identified by bulk RNA-seq data,a GC predictive classifier was constructed using the Least absolute shrinkage and selection operator(LASSO)and random forest methods.The LASSO classifier showed good performance in both validation and model verification using The Cancer Genome Atlas and Genotype-Tissue Expression(GTEx)datasets[area under the curve(AUC)_min=0.988,AUC_1se=0.994],and the random forest model also achieved good results with the validation set(AUC=0.92).Genes TIMP1,PLOD3,CKS2,TYMP,TNFRSF10B,CPNE1,GDF15,BCAP31,and CLDN7 were identified to have high importance values in multiple GC predictive models,and KM-PLOTTER analysis showed their relevance to GC prognosis,suggesting their potential for use in GC diagnosis and treatment.CONCLUSION A predictive classifier was established based on the analysis of RNA-seq data,and the genes in it are expected to serve as auxiliary markers in the clinical diagnosis of GC.

无创模型在慢性乙型肝炎肝纤维化诊断中的价值

背景肝活检是判断乙型肝炎肝纤维化的金标准,因其为有创的检查,临床应用有一定局限性,因此无创性诊断的评估受到关注.目的评价10个无创模型指数对慢性乙型肝炎肝纤维化的诊断价值.方法收集2003-06至2019-08间的慢性乙型肝炎患者1030例,所有病例均接受了肝活检,并同时检测了血液、B超等指标.按照公式计算模型的指数分别为天冬氨酸氨基转移酶/丙氨酸氨基转移酶比值(AST-to-ALT ratio,AAR)、AST/血小板计数比值(AST-to platelet ratio index,APRI)、年龄-血小板指数(age platelet index,API)、肝硬化判别式值(cirrhosis discriminant score,CDS)、FIB-4指数(fibrosis index based on the four factors,FIB-4)、γ-谷氨酰转肽酶/血小板计数(gamma-glutamyltranspeptidase to platelet ratio,GPR)、S指数(S-index,S)、脾脏/血小板比值指数(spleen to platelet ratio index,SPRI)、年龄-脾脏/血小板比值指数(age-spleen to platelet ratio index,ASPRI),FV(作者的模型),并利用ROC曲线下面积(area under receiver operating characteristiccurve,AUROC)评价每个模型在肝纤维化诊断中的临床价值.结果所有模型指数均与肝纤维化分期相关(r=0.215、0.382、0.629、0.449、0.612、0.618、0.654、0.658、0.707、0.775,均P<0.05).诊断F2-3的AUROC较好的为:FV(0.834)和ASPRI(0.796),灵敏度为78.8%和70.2%,特异度为74.0%和76.1%,准确率分别为76.3%和73.3%.F4为:FV(0.928)和ASPRI(0.912),灵敏度为85.4%和89.4%,特异度为85.0%和77.3%,阴性预测值为96.2%和96.5%、阴性似然比为0.172和0.137、准确率为85.1%和79.7%.结论FV和ASPRI是各项无创模型中诊断价值准确率最好的,尤其诊断早期肝硬化方面更具优势.

早期胃癌内镜黏膜下剥离术后出血危险因素的Meta分析

目的分析早期胃癌(EGC)内镜黏膜下剥离术后出血(PEB)的危险因素。方法搜索中国知网、万方、维普数据库、中国生物医学文献数据库、PubMed、Embase、谷歌学术、Cochrane Library和Web ofScience等数据库中关于EGC发生PEB的文章,使用纽卡斯尔-渥太华量表(NOS)对获取的文献进行质量评价。结果共纳入9篇文献,研究对象5719例,发生PEB 282例(4.93%)。Meta分析结果显示:男性(O^R:1.73,95%CI:1.26~2.37)、溃疡阳性(O^R:1.83,95%CI:1.04~3.22)、抗血栓类药物(O^R:2.17,95%CI:1.65~2.86)、操作时间(MD:12.48,95%CI:1.72~23.23)、病灶切除大小(MD:5.30,95%CI:3.32~7.29)和浸润深度(O^R:1.53,95%CI:1.04~2.26)是EGC发生PEB的危险因素。结论男性、术中发现溃疡阳性、使用抗血栓类药物、操作时间、病灶切除大小和浸润深度是EGC发生PEB的独立危险因素,尤其是使用抗血栓类药物治疗的患者,要引起足够的重视。

MEG8、TGM2在胃癌组织中的表达及临床意义

背景胃癌(gastric cancer, GC)是常见恶性肿瘤之一,发病率、死亡率均排在全国、乃至全世界前列,是影响人类健康的重要问题.目前仍缺乏GC早期诊断、治疗及GC预后相关的基因靶点.目的探讨母源性表达基因8(maternally expressed gene 8,MEG8)及转谷氨酰胺酶2(transglutaminase2,TGM2)在GC组织中的表达及临床意义.方法通过荧光定量聚合酶链式反应检测30对GC及癌旁组织中MEG8、TGM2表达情况,分析表达情况与GC患者临床病理特征相关性,通过摘录Oncomine数据库中相关研究数据,分析TGM2表达差异性及与GC患者的生存状态的相关性.结果MEG8在GC组织中的表达量低于癌旁组织(0.462±0.082 vs 1.048±0.149), TGM2在GC组织中的表达量高于癌旁组织(1.202±0.143 vs 0.742±0.083),差异具有统计学意义(P <0.05);MEG8表达与年龄、临床分期有关(P<0.05), TGM2表达与临床分期有关(P <0.05);T G M2表达高低与G C患者生存状态无关(P>0.05).结论MEG8、TGM2参与GC的发生发展过程,可作为GC诊断及预后的潜在靶点.

幽门螺杆菌对于溃疡性结肠炎发生发展的临床意义

目的研究溃疡性结肠炎(ulcerative colitis,UC)患者感染幽门螺杆菌(Helicobacter pylori,H.pylori)的情况及两者关系.方法选取146例经肠镜及病理学检查确诊的UC患者为U C组;另选取150例经肠镜检查未见明显病变的健康体检者为对照组.回顾性分析两组经快速尿素酶试验和组织病理活检联合检测方法检测的H.pylori的感染情况.结果 UC组患者146例,27例阳性,H.pylori感染的阳性率为18.49%,对照组150例体检者,64例阳性,H.pylori感染的阳性率42.67%,UC组明显低于对照组,差异有统计学意义(P<0.05).按病变范围:直肠组27例,7例阳性,H.pylori阳性率为21.88%,左半结肠组48例,9例阳性,H.pylori阳性率为18.75%,广泛结肠组66例,11例阳性,H.pylori阳性率为16.67%.三组间比较,差异无统计学意义(P>0.05).活动期UC患者117例(80.14%),缓解期UC患者29例.缓解期H.pylori感染率阳性率最高(37.93%),重度活动期感染率最低(6.25%),差异较为明显(P<0.05).结论 H.pylori感染可能对UC的发生发展起预防保护作用,随疾病严重程度增加,H.pylori阳性率降低.此外加强UC患者的随访依从性也将非常重要.

Randomized controlled trial: Moxibustion and acupuncture for the treatment of Crohn's disease

AIM: To evaluate the clinical efficacy and safety of acupuncture and moxibustion for the treatment of active Crohn's disease(CD).METHODS: Ninety-two patients were equally and randomly divided into the treatment group and received herb-partitioned moxibustion combined with acupuncture, and the control group received wheat bran-partitioned moxibustion combined with superficial acupuncture. The patients received three treatment sessions per week for 12 wk and were followed up for 24 wk. The main outcome was evaluated using the CD Activity Index(CDAI) score, and the secondary outcomes were evaluated using laboratory indicators such as hemoglobin(HGB), C-reactive protein(CRP), erythrocyte sedimentation rate, quality-of-life, endoscopic ratings, and intestinal histology scores.RESULTS: The CDAI scores of both the treatment and control groups were significantly reduced after treatment compared with those measured before treatment. However, the degree of improvement in the treatment group was significantly greater than that of the control group. The improvement in symptoms in patients of the treatment group was sustained at follow-up, whereas that of the control group was not. The overall efficacy of the treatment was significantly greater than that of the control. Both groups demonstrated significant improvements in quality-of-life ratings after treatment, but the improvement was significantly greater in the treatment group than in the control group. In addition, the patients in the treatment group showed significantly increased HGB and significantly decreasedCRP levels and histopathological scores at the end of treatment, whereas the control group did not exhibit significant changes.CONCLUSION: Moxibustion with acupuncture provided significant therapeutic benefits in patients with active CD beyond the placebo effect and is therefore an effective and safe treatment for active CD.

In vivo tracking of human adipose-derived stem cells labeled with ferumoxytol in rats with middle cerebral artery occlusion by magnetic resonance imaging

Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.

胃镜在健康体检人群胃早癌及癌前疾病筛查中的临床意义

目的了解健康人群胃早癌及癌前疾病的发病趋势及特点,探讨健康人群行胃镜检查的重要性,为将来制定胃早癌及癌前疾病的筛查方案提供临床依据.方法选取2015年9月-2018年6月1281例于该院胃镜健康查体人群的镜下及病理结果,并选取同时期内因消化道症状到消化科门诊行胃镜检查的患者1281例作为对照.结果体检组慢性萎缩性胃炎、胃溃疡、胃息肉及胃癌检出率分别为5.62%、5.85%、8.20%和0.16%,其中胃早癌2例.门诊组检出相应疾病率分别为9.84%、8.04%、8.82%及0.86%,其中胃早癌1例,两组检出疾病比较,差异除胃息肉外均有统计学意义;两组检出胃溃疡、胃癌均以男性为主,胃息肉以女性居多.慢性萎缩性胃炎在体检组中以男性为主,但在门诊组中以女性居多(P<0.05);慢性萎缩性胃炎、胃溃疡检出率随着受检者年龄增长检出率增高,胃息肉及胃癌检出与年龄增长无明显相关,但随着年龄升高,疾病检出亦呈增高趋势.两组中慢性萎缩性胃炎在40~50岁和51~60岁中检出率差异明显,胃溃疡在>60岁中检出率差异明显.两组胃息肉检出年龄高峰段为51~60岁及>60岁,各年龄组间差异无统计学意义.胃癌高发于60岁以上人群,随年龄增长检出率增高;两组慢性萎缩性胃炎的萎缩程度差异有统计学意义,体检组萎缩程度明显轻于门诊组,而肠化程度差异无统计学意义;两组胃溃疡中萎缩及肠化程度比较,差异无统计学意义.结论健康体检人群年龄大于40岁的胃癌及癌前疾病检出率相对较高,有必要针对性开展胃镜体检筛查;健康人群胃镜体检可明显提高胃早癌的检出率,组织活检对于疾病的病情程度及预后评估具有重要意义.

Mapping theme trends and knowledge structures for human neural stem cells:a quantitative and co-word biclustering analysis for the 2013-2018 period

Neural stem cells,which are capable of multi-potential differentiation and self-renewal,have recently been shown to have clinical potential for repairing central nervous system tissue damage.However,the theme trends and knowledge structures for human neural stem cells have not yet been studied bibliometrically.In this study,we retrieved 2742 articles from the PubMed database from 2013 to 2018 using "Neural Stem Cells" as the retrieval word.Co-word analysis was conducted to statistically quantify the characteristics and popular themes of human neural stem cell-related studies.Bibliographic data matrices were generated with the Bibliographic Item Co-Occurrence Matrix Builder.We identified 78 high-frequency Medical Subject Heading(MeSH)terms.A visual matrix was built with the repeated bisection method in gCLUTO software.A social network analysis network was generated with Ucinet 6.0 software and GraphPad Prism 5 software.The analyses demonstrated that in the 6-year period,hot topics were clustered into five categories.As suggested by the constructed strategic diagram,studies related to cytology and physiology were well-developed,whereas those related to neural stem cell applications,tissue engineering,metabolism and cell signaling,and neural stem cell pathology and virology remained immature.Neural stem cell therapy for stroke and Parkinson’s disease,the genetics of microRNAs and brain neoplasms,as well as neuroprotective agents,Zika virus,Notch receptor,neural crest and embryonic stem cells were identified as emerging hot spots.These undeveloped themes and popular topics are potential points of focus for new studies on human neural stem cells.

Effects of phenolic acids on soil nitrogen mineralization over successive rotations in Chinese fir plantations

Phenolic acids are secondary metabolites of plants that significantly affect nutrient cycling processes.To investigate such effects,the soil available nitrogen(N)content,phenolic acid content,and net N mineralization rate in three successive rotations of Chinese fir plantations in subtropical China were investigated.Net N mineralization and nitrification rates in soils treated with phenolic acids were measured in an ex situ experiment.Compared with first-rotation plantations(FCP),the contents of total soil nitrogen and nitrate in second(SCP)-and third-rotation plantations(TCP)decreased,and that of soil ammonium increased.Soil net N mineralization rates in the second-and third-rotation plantations also increased by 17.8%and 39.9%,respectively.In contrast,soil net nitrification rates decreased by 18.0%and 25.0%,respectively.The concentrations of total phenolic acids in the FCP soils(123.22±6.02 nmol g^-1)were 3.0%and 17.9%higher than in the SCP(119.68±11.69 nmol g^-1)and TCP(104.51±8.57 nmol g^-1,respectively).The total content of phenolic acids was significantly correlated with the rates of net soil N mineralization and net nitrification.The ex situ experiment showed that the net N mineralization rates in soils treated with high(HCPA,0.07 mg N kg^-1 day^-1)and low(LCPA,0.18 mg N kg^-1 day^-1)concentrations of phenolic acids significantly decreased by 78.6%and 42.6%,respectively,comparing with that in control(0.32 mg N kg^-1 day^-1).Soil net nitrification rates under HCPA and LCPA were significantly higher than that of the control.The results suggested that low contents of phenolic acids in soil over successive rotations increased soil net N mineralization rates and decreased net nitrification rates,leading to consequent reductions in the nitrate content and enhancement of the ammonium content,then resulting in enhancing the conservation of soil N of successive rotations in Chinese fir plantation.

Caveolin-1 downregulation promotes the dopaminergic neuron-like differentiation of human adipose-derived mesenchymal stem cells

Previous studies have shown that caveolin-1 is involved in regulating the differentiation of mesenchymal stem cells.However,its role in the differentiation of human adipose mesenchymal stem cells into dopaminergic neurons remains unclear.The aim of this study was to investigate whether caveolin-1 regulates the differentiation of human adipose mesenchymal stem cells into dopaminergic-like neurons.We also examined whether the expression of caveolin-1 could be modulated by RNA interference technology to promote the differentiation of human adipose mesenchymal stem cells into dopaminergic-like neurons.The differentiation of human adipose mesenchymal stem cells into dopaminergic neurons was evaluated morphologically and by examining expression of the markers tyrosine hydroxylase,Lmx1a and Nurr1.The analyses revealed that during the differentiation of human adipose mesenchymal stem cells into dopaminergic neurons,the expression of caveolin-1 is decreased.Notably,the downregulation of caveolin-1 promoted the differentiation of human adipose mesenchymal stem cells into dopaminergic-like neurons,and it increased the expression of tyrosine hydroxylase,Lmx1a and Nurr1.Together,our findings suggest that caveolin-1 plays a negative regulatory role in the differentiation of dopaminergic-like neurons from stem cells,and it may therefore be a potential molecular target for strategies for regulating the differentiation of these cells.This study was approved by the Medical Ethics Committee of the First Affiliated Hospital of Dalian Medical University of China(approval No.PJ-KS-KY-2020-54)on March 7,2017.

Joint Subcarrier and Power Allocation for Multi-UAV Systems

This paper investigates subcarrier and power allocation in a multi-UAV OFDM system.The study considers a practical scenario,where certain subcarriers are unavailable for dynamic subcarrier allocation,on account of pre-allocation for burst transmissions.We first propose a novel iterative algorithm to jointly optimize subcarrier and power allocation,so as to maximize the sum rate of the uplink transmission in the multiUAV OFDM system.The key idea behind our solution is converting the nontrivial allocation problem into a weighted mean square error(MSE) problem.By this means,the allocation problem can be solved by the alternating optimization method.Besides,aiming at a lower-complexity solution,we propose a heuristic allocation scheme,where subcarrier allocation and transmit power allocation are separately optimized.In the heuristic scheme,closedform solution can be obtained for power allocation.Simulation results demonstrate that in the presence of stretched subcarrier resource,the proposed iterative joint optimization algorithm can significantly outperform the heuristic scheme,offering a higher sum rate.

Research on Key Issues of Consistency Analysis of Vehicle Steering Characteristics

Given the global lack of effective analysis methods for the impact of design parameter tolerance on performance deviation in the vehicle proof-of-concept stage,it is difficult to decompose performance tolerance to design parameter tolerance.This study proposes a set of consistency analysis methods for vehicle steering performance.The process of consistency analysis and control of automotive performance in the conceptual design phase is proposed for the first time.A vehicle dynamics model is constructed,and the multi-objective optimization software Isight is used to optimize the steering performance of the car.Sensitivity analysis is used to optimize the design performance value.The tolerance interval of the performance is obtained by comparing the original car performance value with the optimized value.With the help of layer-by-layer decomposition theory and interval mathematics,automotive performance tolerance has been decomposed into design parameter tolerance.Through simulation and real vehicle experiments,the validity of the consistency analysis and control method presented in this paper are verified.The decomposition from parameter tolerance to performance tolerance can be achieved at the conceptual design stage.

Human umbilical cord-derived mesenchymal stem cells promote repair of neonatal brain injury caused by hypoxia/ischemia in rats

Administration of human umbilical cord-derived mesenchymal stem cells(hUC-MSCs)is believed to be an effective method for treating neurodevelopmental disorde rs.In this study,we investigated the possibility of hUC-MSCs treatment of neonatal hypoxic/ischemic brain injury associated with maternal immune activation and the underlying mechanism.We established neonatal rat models of hypoxic/ischemic brain injury by exposing pregnant rats to lipopolysaccharide on day 16 or 17 of pregnancy.Rat offspring were intranasally administe red hUC-MSCs on postnatal day 14.We found that polypyrimidine tract-binding protein-1(PTBP-1)participated in the regulation of lipopolysaccharide-induced maternal immune activation,which led to neonatal hypoxic/ischemic brain injury.Intranasal delive ry of hUC-MSCs inhibited PTBP-1 expression,alleviated neonatal brain injury-related inflammation,and regulated the number and function of glial fibrillary acidic protein-positive astrocytes,there by promoting plastic regeneration of neurons and im p roving brain function.These findings suggest that hUC-MSCs can effectively promote the repair of neonatal hypoxic/ischemic brain injury related to maternal immune activation through inhibition of PTBP-1 expression and astrocyte activation.