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Meta-Auto-Decoder:a Meta-Learning-Based Reduced Order Model for Solving Parametric Partial Differential Equations
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作者 Zhanhong Ye Xiang Huang +1 位作者 hongsheng liu Bin Dong 《Communications on Applied Mathematics and Computation》 EI 2024年第2期1096-1130,共35页
Many important problems in science and engineering require solving the so-called parametric partial differential equations(PDEs),i.e.,PDEs with different physical parameters,boundary conditions,shapes of computational... Many important problems in science and engineering require solving the so-called parametric partial differential equations(PDEs),i.e.,PDEs with different physical parameters,boundary conditions,shapes of computational domains,etc.Typical reduced order modeling techniques accelerate the solution of the parametric PDEs by projecting them onto a linear trial manifold constructed in the ofline stage.These methods often need a predefined mesh as well as a series of precomputed solution snapshots,and may struggle to balance between the efficiency and accuracy due to the limitation of the linear ansatz.Utilizing the nonlinear representation of neural networks(NNs),we propose the Meta-Auto-Decoder(MAD)to construct a nonlinear trial manifold,whose best possible performance is measured theoretically by the decoder width.Based on the meta-learning concept,the trial manifold can be learned in a mesh-free and unsupervised way during the pre-training stage.Fast adaptation to new(possibly heterogeneous)PDE parameters is enabled by searching on this trial manifold,and optionally fine-tuning the trial manifold at the same time.Extensive numerical experiments show that the MAD method exhibits a faster convergence speed without losing the accuracy than other deep learning-based methods. 展开更多
关键词 Parametric partial differential equations(PDEs) META-LEARNING Reduced order modeling Neural networks(NNs) Auto-decoder
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Optimization of Extraction Process for Total Flavonoids from Penthorum chinense Pursh and Comparison of Their Contents from Different Parts
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作者 hongsheng liu Jiqiang YAO +2 位作者 Xue BAI Jianying KANG Yefei YUAN 《Medicinal Plant》 2024年第2期10-14,共5页
[Objectives]This study was conducted to optimize the extraction process of total flavonoids from Penthorum chinense Pursh and compare their contents from different parts.[Methods]Single factor and orthogonal experimen... [Objectives]This study was conducted to optimize the extraction process of total flavonoids from Penthorum chinense Pursh and compare their contents from different parts.[Methods]Single factor and orthogonal experiments were designed to optimize the extraction process of total flavonoids from P.chinense Pursh with the volume fraction of ethanol,the ratio of material to liquid,heating reflux extraction time and extraction times as factors,and the content of total flavonoids as the index.A verification test was carried out.The optimized extraction process was adopted to compare the contents of total flavonoids from different parts of P.chinense Pursh.[Results]The best extraction process was extracting the powder of P.chinense Pursh for 2.0 h with 20 times of 55%ethanol by reflux twice.Under this condition,the contents of total flavonoids were 3.63%,8.90%,11.28%,and 4.36%from stems,leaves,flowers and whole grass of P.chinense Pursh,respectively.[Conclusions]The process is reasonable,feasible and stable,and can effectively extract total flavonoids from P.chinense Pursh.The contents of total flavonoids from different parts of P.chinense Pursh were quite different,and the value was higher in the leaves and flowers,so the proportions of leaves and flowers should be paid attention to in the industrial processing of P.chinense Pursh. 展开更多
关键词 Penthorum chinense Pursh Total flavonoids Orthogonal experiments Extraction process Content determination
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DeBakey Type III Aortic Dissection Causing Bowel Necrosis: A Case Report
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作者 Jinhu Kong Jiazheng Li +2 位作者 Haiyang Hu Shangyun Pan hongsheng liu 《Journal of Clinical and Nursing Research》 2024年第8期159-162,共4页
Rationale:Aortic dissection is a life-threatening medical emergency associated with high morbidity and mortality.Preoperative mesenteric malperfusion increases the surgical risk and mortality in patients with type B a... Rationale:Aortic dissection is a life-threatening medical emergency associated with high morbidity and mortality.Preoperative mesenteric malperfusion increases the surgical risk and mortality in patients with type B aortic dissection.For DeBakey type III B patients involving most of the thoracoabdominal aorta,endovascular treatment to improve true lumen perfusion may have limited benefits.Organ reperfusion on-time is crucial.Patient concerns:A 38-year-old man was admitted with sudden severe upper abdominal pain.Emergency CTA of the entire aorta revealed an aortic dissection with an entry tear in the descending aortic arch involving the celiac trunk,superior mesenteric artery,bilateral common iliac arteries and right external iliac artery,with thrombosis in the superior mesenteric artery.Diagnoses:The patient was diagnosed with DeBakey type III aortic dissection with mesenteric artery embolism.Enhanced chest CT showed the entry tear location and involvement of major arteries.Angiography confirmed partial blood flow in the superior mesenteric artery.Interventions:The patient underwent endovascular aortic stent-graft implantation through the left femoral artery,covering the descending aortic arch and sealing the entry tear.Postoperatively,the patient received intensive care,including ventilatory support,CRRT,anti-infection therapy,vasoactive drugs and lumbar cistern drainage.Outcomes:Two weeks postoperatively,the patient developed massive black stools,indicative of intestinal obstruction and necrosis.Exploratory laparotomy revealed ischemic necrosis and rupture of the stomach,small intestine,and colon.Despite surgical efforts,the patient’s condition deteriorated,leading to death from severe infection,acid-base imbalance and multiple organ failure. 展开更多
关键词 Abdominal pain Aortic dissection Arterial embolism Mesenteric artery
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混凝-絮凝沉淀处理石墨烯废水工艺研究在实验教学中的设计与探索 被引量:2
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作者 顾泽宇 张昕 +5 位作者 胥文静 王洪淇 王婷 孙佳垚 刘洪胜 邓进军 《大学化学》 CAS 2023年第8期118-127,共10页
随着石墨烯产业的兴起,强酸高氟高金属离子废水的排放量也与日俱增。本实验在石墨烯废水处理研究基础上设计了一个综合创新实验。采用了单一混凝、中和混凝、混凝絮凝、中和混凝絮凝四种方式处理石墨烯模拟废水,比较其对氟离子、金属离... 随着石墨烯产业的兴起,强酸高氟高金属离子废水的排放量也与日俱增。本实验在石墨烯废水处理研究基础上设计了一个综合创新实验。采用了单一混凝、中和混凝、混凝絮凝、中和混凝絮凝四种方式处理石墨烯模拟废水,比较其对氟离子、金属离子等污染物的去除效果,利用离子色谱、X射线粉末衍射仪等对污水中的离子含量与沉淀物进行分析。研究结果表明,氢氧化钠、氢氧化钙与絮凝剂联用效果最佳,其除氟率达98%,金属离子去除率达99.5%,产渣量较传统工艺减少50%以上。该实验操作方便,现象易于观察;实验内容突出理论与实践相结合,不仅充实了实验课程的教学设计,也引导学生熟悉工业生产实际、提高环境保护意识、掌握化学相关软件的使用及数据分析处理的能力,符合应用型本科院校培养学生综合能力的要求。 展开更多
关键词 石墨烯废水 混凝沉淀 絮凝沉淀 综合实验
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Reconstruction and stability of Fe_(3)O_(4)(001)surface:An investigation based on particle swarm optimization and machine learning
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作者 柳洪盛 赵圆圆 +2 位作者 邱实 赵纪军 高峻峰 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第5期27-31,共5页
Magnetite nanoparticles show promising applications in drug delivery,catalysis,and spintronics.The surface of magnetite plays an important role in these applications.Therefore,it is critical to understand the surface ... Magnetite nanoparticles show promising applications in drug delivery,catalysis,and spintronics.The surface of magnetite plays an important role in these applications.Therefore,it is critical to understand the surface structure of Fe_(3)O_(4)at atomic scale.Here,using a combination of first-principles calculations,particle swarm optimization(PSO)method and machine learning,we investigate the possible reconstruction and stability of Fe_(3)O_(4)(001)surface.The results show that besides the subsurface cation vacancy(SCV)reconstruction,an A layer with Fe vacancy(A-layer-V_(Fe))reconstruction of the(001)surface also shows very low surface energy especially at oxygen poor condition.Molecular dynamics simulation based on the iron–oxygen interaction potential function fitted by machine learning further confirms the thermodynamic stability of the A-layer-V_(Fe)reconstruction.Our results are also instructive for the study of surface reconstruction of other metal oxides. 展开更多
关键词 surface reconstruction magnetite surface particle swarm optimization machine learning
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术前恶性不除外手术病理确诊肺部良性病变297例患者临床-放射-病理特征分析:一项中国单中心回顾性队列研究 被引量:13
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作者 留永健 陈闽江 +13 位作者 郭超 钟巍 叶秋月 赵静 周晴 高晓星 刘潇衍 梁红格 石岳泉 蒋德利娜 刘洪生 徐燕 李单青 王孟昭 《中国肺癌杂志》 CAS CSCD 北大核心 2020年第9期792-799,共8页
背景与目的随着癌症早筛意识的提高,低剂量计算机断层扫描(low-dose computed tomography,LDCT)用于肺癌筛查在中国广泛开展。尽管有部分胸部LDCT筛查所见的肺部病灶是肿瘤病灶,但大多数的肺部结节是良性病变。如何有效的对肺部病灶进... 背景与目的随着癌症早筛意识的提高,低剂量计算机断层扫描(low-dose computed tomography,LDCT)用于肺癌筛查在中国广泛开展。尽管有部分胸部LDCT筛查所见的肺部病灶是肿瘤病灶,但大多数的肺部结节是良性病变。如何有效的对肺部病灶进行术前鉴别,如何降低部分可避免手术的良性疾病的手术切除比例,是需要关注的问题。方法本研究纳入2017年1月1日-2018年12月31日期间北京协和医院诊治的,术前考虑肺部恶性病变不能除外,经手术病理确认为良性病变的患者,回顾性分析患者临床信息。结果 297例患者纳入本研究,占我院肺部病灶行肺部手术治疗患者的9.8%。197例(66.3%)患者因体检行LDCT筛查发现肺部病灶。肺部病变胸部CT影像学评估情况,可评估的323个病灶,平均长径为(17.9±12.1)mm,直径≥8 mm的占91.0%,实性最多见(212/323, 65.6%),此类肺部病灶可有毛刺征(71/323, 22.0%)、分叶征(94/323, 29.1%)、胸膜牵拉征(81/323, 25.1%)、血管集束征(130/323, 40.2%)、空泡征(23/323, 7.1%)等,提示恶性病变的影像学特征。292例(98.3%)行电视辅助胸腔镜手术(video-assisted thoracoscopic surgery, VATS),232例(78.1%)患者行肺楔形切除术,13例(4.4%)行肺段切除术,51例(17.2%)患者行肺叶切除术。4例(1.3%)患者出现手术并发症。术后病理类型前3位的是感染性疾病98例(33.0%)、炎性结节96例(32.3%)和错构瘤64例(21.5%)。结论因术前不能排除恶性而行手术切除的肺部良性病灶,影像学表现以实性病灶多见,但多具有提示恶性的影像学特征。VATS可作为一种明确病原病理的重要活检方式。此类病灶病理结果以感染性疾病和炎性结节最为常见,错构瘤第三。 展开更多
关键词 肺部良性病变 肺结节 肺肿瘤 肺癌筛查
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新型冠状病毒肺炎疫情期间肺癌患者临床管理 被引量:17
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作者 徐燕 刘洪生 +1 位作者 胡克 王孟昭 《中国肺癌杂志》 CAS CSCD 北大核心 2020年第3期136-141,共6页
自2019年12月底以来,湖北省武汉市陆续发现多例新型冠状病毒肺炎(简称:新冠肺炎,2019 novel coronavirusdisease,COVID-19),并在全国范围内蔓延。随着新冠肺炎疫情的蔓延,肺癌患者的常规医疗受到影响。由于肺癌患者接受抗肿瘤治疗后免... 自2019年12月底以来,湖北省武汉市陆续发现多例新型冠状病毒肺炎(简称:新冠肺炎,2019 novel coronavirusdisease,COVID-19),并在全国范围内蔓延。随着新冠肺炎疫情的蔓延,肺癌患者的常规医疗受到影响。由于肺癌患者接受抗肿瘤治疗后免疫力低,合并感染后症状重,应是疫情防治的重点对象,肺癌患者对新冠肺炎的防范措施日益受到关注。复杂严峻的新冠肺炎疫情下,接受抗肿瘤治疗的肺癌患者如出现发热及呼吸道症状,更需要仔细地进行鉴别诊断,评估新冠肺炎感染的风险。对于肺癌患者,在新冠肺炎疫情期间,需要进行精细化和个体化的管理,最大程度地保护患者,有效防范新冠肺炎。 展开更多
关键词 肺肿瘤 患者管理 新型冠状病毒肺炎
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A review of nonlinear piezoelectric energy harvesting interface circuits in discrete components 被引量:2
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作者 Bin ZHANG hongsheng liu +1 位作者 Shengxi ZHOU Jun GAO 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2022年第7期1001-1026,共26页
Piezoelectric energy harvesting is considered as an ideal power resource for low-power consumption gadgets in vibrational environments.The energy extraction efficiency depends highly on the interface circuit,and shoul... Piezoelectric energy harvesting is considered as an ideal power resource for low-power consumption gadgets in vibrational environments.The energy extraction efficiency depends highly on the interface circuit,and should be highly improved to meet the power requirements.The nonlinear interface circuits in discrete components have been extensively explored and developed with the advantages of easy implementation,stable operation,high efficiency,and low cost.This paper reviews the state-of-the-art progress of nonlinear piezoelectric energy harvesting interface circuits in discrete components.First,the working principles and the advantages/disadvantages of four classical interface circuits are described.Then,the improved circuits based on the four typical circuits and other types of circuits are introduced in detail,and the advantages/disadvantages,output power,efficiency,energy consumption,and practicability of these circuits are analyzed.Finally,the future development trends of nonlinear piezoelectric energy harvesting circuits,e.g.,self-powered extraction,low-power consumption,and broadband characteristic,are predicted. 展开更多
关键词 PIEZOELECTRIC NONLINEAR energy harvesting discrete component interface circuit
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Decreased invasion ability of hypotaurine synthesis deficient glioma cells was partially due to hypomethylation of Wnt5a promoter 被引量:1
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作者 Hong TIAN Peiyu CONG +4 位作者 Ruiqun QI Xinghua GAO Xin liu hongsheng liu Fengping SHAN 《BIOCELL》 SCIE 2017年第1期27-32,共6页
Glioma is one of the lethal central nervous system tumors.The infiltrative and invasive growth nature makes it difficult to identify the boundary between glioma and the normal tissues,resulting in inevitable recurrenc... Glioma is one of the lethal central nervous system tumors.The infiltrative and invasive growth nature makes it difficult to identify the boundary between glioma and the normal tissues,resulting in inevitable recurrence after surgery operation.Gliomas do not metastasize,so to prevent the residual tumor from proliferating or invading is a key challenge.Previous report indicated that hypotaurine could facilitate glioma invasion and suppress demethylases’activities.Using a hypotaurine synthesis deficient U251 cell line,we proved that the cells invasion ability was impaired.Gene expression profile analysis exhibited that knocking down one of the key enzymes of hypotaurine synthesis,2-aminoethanethiol dioxygenase(ADO),significantly affected the extracellular matrix-receptor process.Of that process,Wnt5a expression was severely upregulated by decreased intracellular ADO expression.Cells cultured at the presence of hypotaurine showed a decrease in intracellular Wnt5a protein and mRNA levels.This phenotype was due to hypermethylation of Wnt5a promoter,which was most likely the result of hypotaurine’s inhibiting demethylases activities.Collectively,this study demonstrated that hypotaurine synthesis deficient U251 cells were prone to epigenetic modification and Wnt5a seemed to be a tumor suppressor under that circumstance.This tumor suppression effect is warranted to be reevaluated in real tumor samples and the relevant evidence might contribute to develop new glioma interference strategies. 展开更多
关键词 Glioma WNT5A HYPOTAURINE Tumor invasiveness
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Central Brain Herniation Secondary to Influenza-Related Encephalopathy in a Pontocerebellar Hypoplasia Child: A Case Report and Review
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作者 Weiqiang Xiao Peiqing Li +4 位作者 Yuzhi Yao Sida Yang Suyun Li Shuyao Ning hongsheng liu 《Journal of Behavioral and Brain Science》 2020年第6期257-264,共8页
Influenza-associated encephalopathy (IAE) can perform as varying patterns of neuroimaging. Central brain herniation (CBH) secondary to IAE is rare;it may be a bad prognosis. Here, we presented a 4-year-old girl with i... Influenza-associated encephalopathy (IAE) can perform as varying patterns of neuroimaging. Central brain herniation (CBH) secondary to IAE is rare;it may be a bad prognosis. Here, we presented a 4-year-old girl with influenza who had a pontocerebellar hypoplasia (PCH) history;she performed the second Magnetic Resonance Imaging (MRI) on Day 6 from onset, showed the diffuse edema and the occurrence of central herniation;the medulla was “Z-like” folded and the basal cisterns were obliterated completely. Finally she was declared dead. The imbalance between supratentorial and infratentorial pressure can lead to the occurrence of CBH. Severe edema relates to IAE and unstable structure of the posterior fossa might be the main reason for the herniation. MRI is helpful in early diagnosis. Early treatment of cerebral edema in patients with congenital abnormalities of the posterior fossa is vital for their management. 展开更多
关键词 Pontocerebellar Hypoplasia Central Brain Herniation Influenza-Related Encephalopathy Magnetic Resonance Imaging
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Screening of Potent Inhibitor of H1N1 Influenza NS1 CPSF30 Binding Pocket by Molecular Docking
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作者 Li Zhang Jian Zhao +2 位作者 Guowei Ding Xuejiao Li hongsheng liu 《Advances in Infectious Diseases》 2012年第4期92-96,共5页
The swine flu, H1N1 virus was outbroken in Mexico and the United States in April 2009 and then rapidly spread worldwide. The World Health Organization declared that the outbreak of influenza is caused by a new subtype... The swine flu, H1N1 virus was outbroken in Mexico and the United States in April 2009 and then rapidly spread worldwide. The World Health Organization declared that the outbreak of influenza is caused by a new subtype of influenza H1N1 influenza virus. And researchers have isolated some oseltamivir resistance strains in 2009 swine flu which makes the imminency of research and development of new anti influenza drug. The CPSF30 binding pocket of effector domain in NS1 protein is very important in the replication of influanza A virus and is a new attractive anti flu drug target. But up to now there is no antiviral drug target this pocket. Here we employ molecular docking to screening of about 200,000 compounds. We find four novel compounds with high binding energy. Binding comformation analysis revealed that these small molecules can interact with the binding pocket by some strong hydrophobic interaction. This study find some novel small molecules can be used as lead compounds in the development of new antiinfluenza drug based on CPSF30 pocket. 展开更多
关键词 CPSF30 BINDING POCKET Molecular DOCKING INFLUENZA A H1N1
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Relationship belween Gene Expression of bFGF and Prolifercrtive Activity in Meningioma
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作者 Zhongqiu Luo Jinhuan Wang +6 位作者 Peiyu Pu Xinnu Xu Youping Zhang hongsheng liu Ping liu Jianbing Qi Mu Li 《Chinese Journal of Clinical Oncology》 CSCD 2005年第5期805-809,共5页
OBJECTIVE To study the relationship between bFGF gene expression and proliferative activity in meningiomas. METHODS Thirty-seven samples of meningioma were examed using Northern hybridization for bFGF-gene expression ... OBJECTIVE To study the relationship between bFGF gene expression and proliferative activity in meningiomas. METHODS Thirty-seven samples of meningioma were examed using Northern hybridization for bFGF-gene expression and immunohistochemi- stry for bFGF protein expression and the Ki-67LI. RESULTS bFGF mRNA was detected in 22 meningiomas of Grade Ⅰ and in all samples of Grade Ⅱ and Ⅲ. Six of the Grade Ⅰ tumors were negative, giving an overall positive rate of 83.8 % for bFGF mRNA. Autoradiography was conducted using a thin scaning apparatus, bFGF mRNA expression compared to that for β-actin was 0.34±0.06 for Grade Ⅰ tumors compared to 0.82±0.12 for Grade Ⅱ and Ⅲ tumors. The difference was highly significant (P〈0.001). The results of immunohistochemistry showed that the number of the positive cells for the bFGF protein was 29.7±7.6% in Grade Ⅰ tumors and 63.2±11.7 % in Grade Ⅱ plus Ⅲ, resulting in a significant difference between them (P〈0.001) . The Ki-67LI was found to be 2.8±1.1% in Grade Ⅰ and 6.5±1.3 % in Grade Ⅱ plus Ⅲ. The former was significantly lower than the later (P〈0.001). CONCLUSION The expression of bFGF was correlated well with the malignancy of the meningiomas. 展开更多
关键词 MENINGIOMA BFGF Ki-67LI.
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The preparation of Garcinia Glycosides solid dispersion and intestinal absorption by rat in situ single pass intestinal perfusion
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作者 Shengnan Li Jingchao Ji +4 位作者 Yinghui Chen Ye Chen Ju liu Yang Wang hongsheng liu 《Journal of Pharmaceutical and Biopharmaceutical Research》 2019年第1期15-20,共6页
Garcinia Glycosides is a candidate drug obtained by structural modification of Gambogic Acid (GA), which was acquired through High Throughput Screening(HTS). As Garcinia Glycosides is an effective but insoluble anti-t... Garcinia Glycosides is a candidate drug obtained by structural modification of Gambogic Acid (GA), which was acquired through High Throughput Screening(HTS). As Garcinia Glycosides is an effective but insoluble anti-tumor drug, the aim of this study was to obtain a solid dispersion form Garcinia Glycosides by using solvent-melt method so that improve the solubility and dissolution rate. The solid dispersion was characterized by High Performance Liquid Chromatography (HPLC), infrared spectroscopy and evaluated the intestinal absorption of the drug by rat in situ single pass intestinal perfusion. The results showed the increase of solubility, dissolution velocity and absorption compared to other forms. This indicated that solid dispersion could greatly improve the relative bioavailability of Garcinia Glycosides in vivo. 展开更多
关键词 GARCINIA GLYCOSIDES solid dispersion INTESTINAL PERFUSION in SITU single-pass PERFUSION method
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机器学习在MALDI-TOF MS鉴定微生物中的应用 被引量:4
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作者 刘宏生 冯华炜 +2 位作者 张力 孟金蕙 董雪 《微生物学报》 CAS CSCD 北大核心 2020年第5期841-855,共15页
基质辅助激光解吸/电离飞行时间质谱(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)是一种新兴的高通量技术,已广泛应用于临床微生物、食品微生物和水产微生物的快速鉴定。如何进一步提... 基质辅助激光解吸/电离飞行时间质谱(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)是一种新兴的高通量技术,已广泛应用于临床微生物、食品微生物和水产微生物的快速鉴定。如何进一步提高MALDI-TOF MS在微生物鉴定中的分辨率是该技术当前面临的一大挑战。为了高效处理大量高维微生物MALDI-TOF MS数据,各种机器学习算法得到了应用。本文综述了机器学习在微生物MALDI-TOFMS鉴定中的应用。首先,本文在介绍机器学习在微生物MALDI-TOF MS分类中的工作流程后,进一步对MALDI-TOF MS的数据特征、MALDI-TOF MS数据库、数据的预处理和模型的性能评估进行了描述。然后讨论了典型的机器学习分类算法和集成学习算法的应用。简单的机器学习算法很难满足微生物MALDI-TOF MS分类的高分辨率的需求,而组合不同机器学习算法和集成学习算法可以获得更好的微生物分类性能。在MALDI-TOF MS数据的预处理方面,小波算法和遗传算法的应用最广,它们结合分类算法可以有效提高MALDI-TOF MS的分类性能。随着微生物MALDI-TOF MS数据量的不断增加,在未来的研究工作中应更重视分类算法的改进、不同算法的选择或组合以及预处理算法的改进。 展开更多
关键词 微生物鉴定 MALDI-TOF MS 机器学习算法 预处理算法
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新型U肋与顶板双面焊接残余应力场的超声冲击调控方法研究 被引量:3
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作者 刘红胜 罗永传 +1 位作者 韩少辉 张清华 《钢结构(中英文)》 2021年第10期25-33,共9页
新型U肋与顶板双面焊接构造相比传统单面焊构造焊接工序更多、焊接残余应力场更为复杂,发展适用于该新型构造焊接残余应力场调控的焊后处理措施对其进一步推广和应用具有重要意义。为探究超声冲击处理技术对该新型构造焊接残余应力场的... 新型U肋与顶板双面焊接构造相比传统单面焊构造焊接工序更多、焊接残余应力场更为复杂,发展适用于该新型构造焊接残余应力场调控的焊后处理措施对其进一步推广和应用具有重要意义。为探究超声冲击处理技术对该新型构造焊接残余应力场的调控效应,利用热-应力顺序分析方法对该新型构造的焊接过程进行模拟,以获得其焊接温度场和焊接残余应力场分布。在此基础上,利用应力、应变初始化技术将焊接残余应力场导入超声冲击模型,使之成为超声冲击模型的初始分析状态。最后,基于动力显式分析方法对超声冲击过程进行模拟,模型中采用质量比例阻尼技术来降低动力显式分析过程中的数值震荡。为说明该多步骤顺序分析有限元模型的合理性,分别从多个方面对模型进行验证:将计算熔化区形状与焊缝形貌进行对比来验证计算温度场的正确性;将计算纵、横向焊接残余应力分布与测试数据对比来验证计算焊接残余应力场的正确性;将计算冲击坑形状与实际形状对比、冲击后残余应力与测试数据对比来说明超声冲击过程模拟的正确性。在有限元模型正确性得到充分验证的基础上,开展超声冲击处理对新型U肋与顶板双面焊构造焊接残余应力场的调控效应研究,并对不同冲击次数和不同冲击速度下焊缝区域残余应力场的变化进行分析。研究结果表明:该多步骤顺序分析有限元模型能够准确模拟超声冲击处理对新型U肋与顶板双面焊接构造焊接残余应力场的调控效应;经超声冲击处理,新型U肋与顶板双面焊接构造焊趾区域残余应力状态由拉转为压,应力降低幅度最大值为427.2 MPa;自顶板下表面至一定深度范围内均存在残余压应力,且最大压应力值出现在顶板亚表面;随超声冲击针冲击次数增加,新型U肋与顶板双面焊构造顶板下表面残余压应力量值、冲击影响深度均逐渐增大;随超声冲击针冲击速度增大,所引入的残余压应力最大值的分布深度逐渐增大,当冲击速度增大至7 m/s时,残余压应力最大值的分布深度已达0.8 mm。 展开更多
关键词 桥梁工程 正交异性钢桥面板 新型U肋与顶板双面焊构造 超声冲击处理 有限元分析
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Microscopic insight into the single step growth of in-plane heterostructures between graphene and hexagonal boron nitride 被引量:2
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作者 Thanh Hai Nguyen Daniele Perilli +5 位作者 Mattia Cattelan hongsheng liu Francesco Sedona Neil A. Fox Cristiana Di Valentin Stefano Agnoli 《Nano Research》 SCIE EI CAS CSCD 2019年第3期675-682,共8页
Graphene-h-BN hybrid nanostructures are grown in one step on the Pt(111) surface by ultra-high vacuum chemical vapor deposition using a single precursor,the dimethylamino borane complex.By varying the deposition condi... Graphene-h-BN hybrid nanostructures are grown in one step on the Pt(111) surface by ultra-high vacuum chemical vapor deposition using a single precursor,the dimethylamino borane complex.By varying the deposition conditions,different nanostructures ranging from a fully continuous hybrid monolayer to well-separated Janus nanodots can be obtained.The growth starts with heterogeneous nucleation on morphological defects such as Pt step edges and proceeds by the addition of small clusters formed by the decomposition of the dimethylamino borane complex.Scanning tunneling microscopy measurements indicate that a sharp zigzag in-plane boundary is formed when graphene grows aligned with the Pt substrate and consequently with the h-BN layer as well.When graphene is rotated by 30°,the graphene armchair edges are seamlessly connected to h-BN zigzag edges.This is confirmed by a thorough density functional theory (DFT) study.Angle resolved photoemission spectroscopy (ARPES) data suggests that both h-BN and graphene present the typical electronic structure of self-standing non-interacting materials. 展开更多
关键词 GRAPHENE H-BN HETEROSTRUCTURES seanning TUNNELING microscopy density functional theory (DFT)
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Adaptor protein APPL1 interacts with EGFR to orchestrate EGF-stimulated signaling 被引量:2
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作者 Jiajia Zhou hongsheng liu +2 位作者 Shu Zhou Ping He Xing liu 《Science Bulletin》 SCIE EI CAS CSCD 2016年第19期1504-1512,共9页
Epidermal growth factor receptor (EGFR) mediates multiple signaling pathways that regulate cell migration, proliferation, and differentiation. Adaptor pro- tein APPL1 has been reported to function as a downstream ef... Epidermal growth factor receptor (EGFR) mediates multiple signaling pathways that regulate cell migration, proliferation, and differentiation. Adaptor pro- tein APPL1 has been reported to function as a downstream effector of EGFR signaling pathway. However, molecular mechanisms underlying the role of APPL1 downstream of EGFR signaling remains elusive. Here, we identified APPL1 as a critical molecule that interacts with EGFR. Suppression of APPL 1 by siRNA inhibited EGF-stimulated Akt phosphorylation. Functionally, EGF stimulation of cells caused phosphorylation of APPL1 at Ser636, which subsequently promoted the interaction between APPL1 and EGFR, indicating that APPL1 sensitizes EGF stimulation by acting at a site downstream of the EGFR signaling. Importantly, non-phosphorylatable mutant of APPL1 reduced cell migration compared with wild-type APPL1 in an Akt-dependent manner. Our study reveals a novel function of APPL1 in EGF signaling and defines a novel molecular mechanism by which phosphorylation of APPL1 upon EGF stimulation regulates cell migration underlying EGF-stimulated Akt pathway. 展开更多
关键词 APPL1 EGF EGFR AKT PHOSPHORYLATION
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Preparation, characterization and pharmacokinetic studies of total paeony glycoside nanocrystals 被引量:2
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作者 Jinfeng Zhang Fan Wu +8 位作者 Jiayi Han Jinghong Rong Yi Li Yu liu Xiao Liang Xin Wang Hao Pan hongsheng liu Lijiang Chen 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2018年第2期99-108,共10页
Total paeony glycoside(TPG) is obtained from Radix Paeoniae Rubra with a variety of bioactivities. However, the low solubility and bioavailability limit its application. The present study aimed to develop TPG nanocr... Total paeony glycoside(TPG) is obtained from Radix Paeoniae Rubra with a variety of bioactivities. However, the low solubility and bioavailability limit its application. The present study aimed to develop TPG nanocrystals to increase the dissolution and then improve the oral bioavailability. TPG nanocrystals were prepared via precipitation and high-pressure homogenization method. The physical-chemical properties of the optimal TPG nanocrystals in terms of particle size, zeta potential, morphology and crystallinity were evaluated. The results showed that TPG nanocrystals had a mean particle size of(210.2±2.5) nm, a polydispersity index of 0.191±0.033 and a zeta potential of(–22.4±1.2) mV. The result of differential scanning calorimetry showed that the nanocrystals were still in crystalline state after the preparation procedure. Transmission electron microscopy(TEM) results showed that the nanosuspension was in spherical shape. The pharmacokinetics of TPG nanocrystals for rats was investigated by liquid chromatography-tandem mass spectroscopy(LC-MS/MS). Compared with the TPG coarse suspension, TPG nanocrystals exhibited significant increase in AUC0–∞(approximately 1.85-fold). Taken together, TPG nanocrystals could be used as a promising drug delivery system due to the enhanced oral bioavailability of TPG. 展开更多
关键词 Total paeony glycoside NANOCRYSTALS High-pressure homogenization PHARMACOKINETICS BIOAVAILABILITY
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