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Communications in Computational Physics 2023年第5期33卷 1509-1513页

作者： Lulu Zhang Wei Cai zhi-qin John xu Institute of Natural Sciences and School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai200240China Department of Mathematics Southern Methodist UniversityDallasTX 75275USA

This note provides a correction of a missing weight constant in the MscaleDNN formula and some comments on the performance of the corrected algorithm.

关键词： Multi-scale DNN PDE solver deep learning

A Linear Frequency Principle Model to Understand the Absence of Overfitting in Neural Networks

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Chinese Physics Letters 2021年第3期38卷 121-126页

作者： Yaoyu Zhang Tao Luo Zheng Ma zhi-qin John xu School of Mathematical Sciences Institute of Natural SciencesMOE-LSCand Qing Yuan Research InstituteShanghai Jiao Tong UniversityShanghai 200240China Shanghai Center for Brain Science and Brain-Inspired Technology Shanghai 200031China

Why heavily parameterized neural networks(NNs) do not overfit the data is an important long standing open question. We propose a phenomenological model of the NN training to explain this non-overfitting puzzle. Our linear frequency principle(LFP) model accounts for a key dynamical feature of NNs: they learn low frequencies first, irrespective of microscopic details. Theory based on our LFP model shows that low frequency dominance of target functions is the key condition for the non-overfitting of NNs and is verified by experiments. Furthermore,through an ideal two-layer NN, we unravel how detailed microscopic NN training dynamics statistically gives rise to an LFP model with quantitative prediction power.

关键词： networks neural details

MOD-Net:A Machine Learning Approach via Model-Operator-Data Network for Solving PDEs

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Communications in Computational Physics 2022年第7期32卷 299-335页

作者： Lulu Zhang Tao Luo Yaoyu Zhang Weinan E zhi-qin John xu Zheng Ma Institute of Natural Sciences and School of Mathematical Sciences Shanghai Jiao Tong UniversityShanghai200240China School of Mathematical Sciences and Institute of Natural Sciences Shanghai Jiao Tong UniversityCMA-ShanghaiShanghai200240China MOE-LSC and qing Yuan Research Institute Shanghai Jiao Tong UniversityShanghai200240China Shanghai Center for Brain Science and Brain-Inspired Technology Shanghai200031China School of Mathematical Sciences Peking UniversityBeijing100871China AI for Science Institute Beijing100080China

In this paper,we propose a machine learning approach via model-operatordata network(MOD-Net)for solving PDEs.A MOD-Net is driven by a model to solve PDEs based on operator representationwith regularization *** linear PDEs,we use a DNN to parameterize the Green’s function and obtain the neural operator to approximate the solution according to the Green’s *** train the DNN,the empirical risk consists of the mean squared loss with the least square formulation or the variational formulation of the governing equation and boundary *** complicated problems,the empirical risk also includes a fewlabels,which are computed on coarse grid points with cheap computation cost and significantly improves the model ***,the labeled dataset works as a regularization in addition to the model *** MOD-Net solves a family of PDEs rather than a specific one and is much more efficient than original neural operator because few expensive labels are *** numerically show MOD-Net is very efficient in solving Poisson equation and one-dimensional radiative transfer *** nonlinear PDEs,the nonlinear MOD-Net can be similarly used as an ansatz for solving nonlinear PDEs,exemplified by solving several nonlinear PDE problems,such as the Burgers equation.

关键词： Deep neural network radiative transfer equation Green’s method neural operator

RECONSTRUCTION OF THE SELLAR FLOOR FOLLOWING TRANSSPHENOIDAL SURGERY USING GELATIN FOAM AND FIBRIN GLUE

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Chinese Medical Sciences Journal 2005年第3期20卷 198-201页

作者： Jian Yin Chang-bao Su zhi-qin xu xue-wei Xia Fei Song Department of Neurosurgery Peking Union Medical College Hospital Chinese Academy of Medical Sciences ＆ Peking Union Medical College Beijing 100730 Department of Neurosurgery the Second Affiliated Hospital Dalian Medical University Dalian 116027

Objective To introduce a new principle of sellar reconstruction and to evaluate the effectiveness of absorbable gelatin foam and fibrin glue for sellar reconstruction. Methods A total of 176 consecutive patients who underwent surgery for pituitary adenomas, cysts, chordomas, or subdiaphragmatic craniopharyngiomas in the sella turcica between January 2001 and April 2003 at Peking Union Medical College Hospital were enrolled. Different techniques of sellar closure and indications for each specific condition were retrospectively reviewed. Results Seventy-seven (43.7%) patients developed a visible cerebrospinal fluid (CSF) leakage during surgery. Intra- operative CSF leakage were repaired simply with gelatin foam and fibrin glue in 62 (35.2%) patients, and with autologous fat graft and sellar floor reconstruction in 15 (8.5%) patients. Postoperative CSF rhinorrhea occurred only in 1 case. There were no visual deterioration, allergic rhinitis, meningitis, pneumocranium, granulomas, or other complications asso- ciated with the reconstruction procedure. Conclusion The procedure of using gelatin foam and fibrin glue and principle of cranial base reconstruction is safe and effective in preventing postoperative complications following transsphenoidal surgery.

关键词： transsphenoidal surgery sellar floor reconstruction cerebrospinal fluid leakage

An Improved Strategy for Efficient Expression and Purification of Soluble HIV-1 Tat Protein in ***

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Virologica Sinica 2009年第6期24卷 518-528页

作者： Shi-meng ZHANG Rong FAN Tian-yi YANG Yi SUN Jing-yun LI qin-zhi xu Ping-kun ZHOU The Department of Radiation Toxicology and Oncology Beijing Institute of Radiation Medicine Beijing100850 China Institute of Microbiology and Epidemiology Beijing 100071 China

Although the endogenous function of Tat has been elucidated in the past twenty years, the study of its exogenous activity has been hampered due to the difficulty of large scale preparation of the active Tat protein. To express the full-length Tat protein in ***, the tat gene was cloned from an HIV infected patient by overlapping PCR. Rare codon usage analysis showed that rare *** codons, especially consecutive rare codons for Arg, account for 14% (14 of 101) rare *** codons in the tat gene. The expression of the HIV-1 tat gene was verified to be very poor in strain BL21 (DE3) due to the abundance of rare codons; however, tat gene expression was found to be very efficient in the host strain of Rosetta-gami B (DE3), which was supplemented with six rare tRNAs for Arg, Leu, Ile and Pro. Subsequent purification revealed that the proteins are soluble and unusually, the tagged Tat can form dimers independent of cystine disulfide bonds. The purity, integrity and molecular weight of the Tat protein were demonstrated by MALDI-TOF mass spectrometry. Reporter gene activating assay was further confirmed by investigating the transactivation activity of the recombinant Tat protein. Our improved strategy for efficient high level expression and purification of soluble Tat protein has paved the way to fully investigate its exogenous function.

关键词： HIV tat gene E.coli Protein expression Codon usage

Pregnancy Combined with Epilepsy and Cerebral Cavernous Malformation

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Chinese Medical Journal 2017年第5期130卷 619-620页

作者： Ya-Lan xu Jun-Tao Liu Yi-Jun Song Xi-Ya Zhou qing-Wei Qi xu-Ming Bian zhi-qin xu Lei Li Department of Obstetrics and Gynecology Peking Union Medical College Hospital Peking Union Medical College Chinese Academy of Medical Sciences Beijing 100730 China Department of Neurosurgery Peking Union Medical College Hospital Peking Union Medical College Chinese Academy of Medical Sciences Beijing 100730 China

INTRODUCTIOIN Cerebral cavernous malformation （CCM）, also known as cavernous angioma, is a type of vascular malformation in the central nervous system. To date, rare cases of CCM and seizure have been reported in pr... 详细信息

关键词： Cerebral Cavernous Malformation Delivery Hemorrhage Pregnancy

Overview of in-situ oxygen production technologies for lunar resources

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 233-255页

作者： Youpeng xu Sheng Pang Liangwei Cong Guoyu Qian Dong Wang Laishi Li Yusheng Wu zhi Wang College of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China CAS Key Laboratory of Green Process and Engineering National Engineering Research Center for Green Recycling of Strategic Metal ResourcesInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial ***,crucial for supporting human life on the Moon,can be extracted from lunar regolith,which is highly rich in oxygen and contains polymetallic *** oxygen and metal extraction can be achieved using existing metallurgical ***,the ample reserves of water ice on the Moon offer another means for oxygen *** paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon,drawing from an analysis of lunar resources and environmental *** delves into the principles,processes,advantages,and drawbacks of water-ice electrolysis,two-step oxygen production from lunar regolith,and one-step oxygen production from lunar *** two-step methods involve hydrogen reduction,carbothermal reduction,and hydrometallurgy,while the one-step methods encompass fluorination/chlorination,high-temperature decomposition,molten salt electrolysis,and molten regolith electrolysis(MOE).Following a thorough comparison of raw materials,equipment,technology,and economic viability,MOE is identified as the most promising approach for future in-situ oxygen production on the *** the corrosion characteristics of molten lunar regolith at high temperatures,along with the Moon's low-gravity environment,the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the *** review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.

关键词： lunar resources in-situ oxygen production space metallurgy molten lunar regolith electrolysis

桂西北地质高背景区有色金属冶炼对周边土壤重金属污染与生态风险评价

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生态学杂志 2021年第8期40卷 2324-2333页

作者：秦旭芝罗志祥季文兵梁鹏苏荣李方刘旭尹娟广西壮族自治区生态环境监测中心南宁530028 广西壮族自治区产品质量检验研究院南宁530000 生态环境部南京环境科学研究所南京210042 国家环境保护土壤管理与污染控制重点实验室南京210042 中国地质大学(北京) 北京100083 广西财经学院南宁530007 南宁师范大学广西西江流域生态环境与一体化发展协同创新中心南宁530031

广西碳酸盐岩分布区是典型的土壤重金属地质高背景区,有色金属冶炼活动进一步增强了土壤重金属累积程度,准确区分冶炼活动与地质背景对区域土壤重金属污染的贡献是源解析研究的难点。本文选定广西典型地质背景区某有色金属冶炼区为研究... 详细信息

广西碳酸盐岩分布区是典型的土壤重金属地质高背景区,有色金属冶炼活动进一步增强了土壤重金属累积程度,准确区分冶炼活动与地质背景对区域土壤重金属污染的贡献是源解析研究的难点。本文选定广西典型地质背景区某有色金属冶炼区为研究区域,研究了土壤中Cd、Hg、As、Pb、Cr、Cu、Zn、Ni等重金属的分布特征和潜在生态风险,采用溯源方法分析了土壤中重金属的来源及贡献率。结果表明,研究区土壤主要污染物为Cd、Zn、As和Pb,表层土壤Cd超标程度较重的区域呈强烈生态风险状态。土壤中Cd、Hg、As、Pb、Cu、Zn主要来源为冶炼活动,Cr、Ni主要来源为地质高背景。Cd、Hg、As、Pb、Cr、Cu、Zn、Ni地质背景因素贡献率分别为:4.8%、71.7%、33.6%、31.0%、92.4%、76.5%、27.3%、99.3%;人为影响因素贡献率分别为:95.2%、28.3%、66.4%、69.0%、7.6%、23.5%、72.7%、0.7%。本研究为准确评价碳酸盐岩矿区土壤重金属污染风险,科学制定土壤重金属污染防控对策具有重要的支持作用。

关键词：有色金属冶炼土壤重金属生态风险

Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury

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Neural Regeneration Research 2025年第5期20卷 1416-1430页

作者： Mou Gao qin Dong Dan Zou zhijun Yang Lili Guo Ruxiang xu Department of Neurosurgery Sichuan Academy of Medical Sciences and Sichuan Provincial People’s HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Department of Neurosurgery Chinese PLA General HospitalBeijingChina Department of Neurology Fu Xing HospitalCapital Medical UniversityBeijingChina

Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and *** previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological ***,the mechanism of CXCR4 upregulation in induced neural stem cells remains *** this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 ***,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial *** agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury ***,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head *** conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neura

关键词： Akt signaling cerebral edema closed head injury Crry CXCR4 induced neural stem cell microglia neuroinflammation

Proteomic analysis reveals the radiosensitization of vanillin derivative bromovanin by targeting G2/M checkpoint and mitotic catastrophe

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Proteomic analysis reveals the radiosensitization of vanilli...