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Discussion on the mechanism of the calcium absorption in the human body

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Chinese Science Bulletin 2001年第16期46卷 1403-1408页

作者： zhang jingkun zhang Zemin YU Ao Central Laboratory Nankai UniversityTianjin 300071China Department of Chemistry Nankai UniversityTianjin 300071China

The present article discusses a new mechanism of calcium absorption in the human body. The mechanism is revealed as follows. First, after food is digested in the stomach, calcium ions (Ca2+) are released. The small intestine secretes amino acid or short peptide chain with small molecular weight automatically, which are called chelating agent; when the calcium ions from the stomach get to the small intestine, the reaction of the chelating agent with the calcium ions occurs, producing the neutral amino acid calcium chelate. Then, this kind of calcium chelate with small molecular weight is absorbed as a whole into the tissues of the small intestine. After being absorbed, in the cell the calcium chelate can break down its chelating bond automatically and decompose into the amino acid and calcium ion again. Finally, the calcium ion goes into blood through portal vein and is transferred to the organs and also deposits on the bone. The reason for the body抯 calcium insufficiency, which has no linear relation with the calcium intake amount, is the lack of the amino acid secreted by the small intestine. The main barrier that influences the calcium absorption is anion pollution. The calcium absorptivity of the body has nothing to do with the solubility of the calcium source out of the body. A new kind of calcium supplement agent——glycine calcium chelate——is synthesized, whose molecular weight is 206.06 (containing a molecular water). If the glycine calcium chelate is used to make calcium supplement agent, about 20 mg calcium element (converted from the glycine calcium chelate, the same below, no longer indicated) per day for one person, 50 mg at most, is enough to maintain the positive balance of calcium metabolism.

关键词： amino acid chelate calcium.

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不同来源间充质干细胞治疗卵巢早衰的机制

中国组织工程研究 2025年第13期29卷 2764-2773页

作者：刘艳艳马园园黄向华张敬坤河北医科大学第二医院河北省石家庄市050000

背景:已经有大量细胞及动物实验证实了间充质干细胞具有改善卵巢功能的作用,部分临床试验也已完成并初步证实了其有效性,为卵巢早衰女性带来了希望。目的:总结并分析近年来关于不同来源间充质干细胞治疗卵巢早衰的机制、研究进展及相关... 详细信息

背景:已经有大量细胞及动物实验证实了间充质干细胞具有改善卵巢功能的作用,部分临床试验也已完成并初步证实了其有效性,为卵巢早衰女性带来了希望。目的:总结并分析近年来关于不同来源间充质干细胞治疗卵巢早衰的机制、研究进展及相关临床试验,为间充质干细胞治疗卵巢早衰的进一步研究及临床应用提供理论依据。方法:以“间充质干细胞,卵巢早衰”及“mesenchymal stem cells,premature ovarian failure”分别作为中、英文关键词,在中国知网、万方数据库、中华医学库及PubMed数据库对相关文献进行检索,最终纳入符合要求的72篇文献进行综述。结果与结论:目前常用于治疗卵巢早衰的间充质干细胞种类有7类,分别为脐带间充质干细胞、骨髓间充质干细胞、胎盘间充质干细胞、经血间充质干细胞、羊膜间充质干细胞、羊水间充质干细胞及脂肪间充质干细胞,涉及作用机制主要包括抑制凋亡促进增殖、抗炎及抑制氧化应激、归巢、促血管生成、抗纤维化、旁分泌、免疫调节、自噬及改善微环境。细胞和动物实验均表明不同来源间充质干细胞可以通过各种机制对卵巢早衰有较好的干预效果,一定程度上延缓了卵巢早衰的进展。如果将来能成功运用于临床,能够很大程度上缓解患者来自心理及生理上的痛苦。但目前临床研究因干细胞来源伦理、具体给药方式及剂量、是否引发严重不良反应等方面缺乏全面且准确的证据,故在未来仍需进行深入探讨,同时远期安全性也有待进一步观察。

关键词：卵巢早衰间充质干细胞颗粒细胞卵泡机制作用方式临床试验诊疗

Multivariate statistical analysis of chemical and stable isotopic data as indicative of groundwater evolution with reduced exploitation

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Geoscience Frontiers 2023年第1期14卷 133-148页

作者： Fei Liu jingkun zhang Shiqin Wang Jiawen Zou Pinna Zhen School of Water Conservancy and Hydropower Hebei University of Engineering19 Taiji RoadHandanHebei 056038China Hebei Key Laboratory of Intelligent Water Conservancy HandanHebei 056038China Key Laboratory of Agricultural Water Resources Center for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyChinese Academy of SciencesShijiazhuang 050021China

Groundwater resources in the North China Plain(NCP)are undergoing tremendous changes in response to the operation of groundwater exploitation reduction(GWER)*** identify groundwater evolution in this complex context,hierarchical cluster analysis(HCA)and principal component analysis(PCA)were combined to interpret an integrated dataset of stable isotopes and chemical data from four sampling campaigns in a pilot area of groundwater *** proposed a novel HCA approach integrating stable isotopes and chemical signals,which successfully partitioned the groundwater samples into the unconfined and the confined water *** isotopic evidence showed that the lateral inflow and the surface water may contribute more to groundwater recharge in this region than local modern *** unconfined water's main hydrochemical types were Na type with mixed anions,and Na-Cl-SO_(4)type,while the confined water was mainly Na-Cl and Na-SO_(4)*** processes mainly involved the dissolution/precipitation of halite,gypsum,Glauber's salt,feldspar,calcite and dolomite,as well as the cation *** results showed that water-rock interaction(i.e.,salinity-based and alkalinity-based processes)predominated the hydrochemical evolution,along with local nitrate contamination resulting from fertilizers and domestic *** GWER project regulated the natural evolution of unconfined water chemistry,and significantly reduced the unconfined water's salinity(mainly Na^(+),Mg^(2+),SO_(4)^(2-)).This may be attributed to upward leakage from low-salinity confined water at some parts of the ***,insignificant changes in the confined water's salinity reflected that the impact of GWER on the confined aquifer was *** study facilitates the groundwater classification effectively in the areas lack of geological data,and enhances the knowledge of groundwater chemical evolution in such a region where groundwater restoration is in progress,with i

关键词： Hydrochemistry Stable isotopes Groundwater evolution Groundwater exploitation reduction Hierarchical cluster analysis Principal component analysis

Molecular evolution of nitrogen-containing compounds in highly mature organic matter: Implications for the hydrocarbon generation potential

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Science China Earth Sciences 2023年第4期66卷 781-796页

作者： jingkun zhang Jian CAO Wenxuan HU Baoli XIANG Ni ZHOU Wanyun MA School of Earth Sciences and Engineering MOE Key Laboratory of Surficial GeochemistryNanjing UniversityNanjing 210023China Research Institute of Experiment and Testing PetroChina Xinjiang Oilfield CompanyKaramay 834000China

Evaluating the hydrocarbon generation potential of highly mature organic matter is a key and critically challenging area of research in petroleum geochemistry. To explore this issue, we used negative ion electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry to investigate the molecular evolution of N-containing compounds in Carboniferous-lower Permian source rocks with a range of maturities in the northwestern Junggar Basin, China. The N1compounds formed from on-fluorescent chlorophyll catabolites(NCCs), which record the characteristics of the residual soluble organic matter. These components remain in the source rocks after hydrocarbon generation and expulsion, and enable evaluation of the hydrocarbon generation potential. The newly defined indexes of molecular evolution, which are the polymerization index P1([DBE 18+DBE 15]/[DBE 12+DBE 9]_N1) and alkylation index R1(RC_(6–35)/RC_(0–5)), combined with the vitrinite reflectance(VR_(o)) and paleo-salinity index(β-carotane/n Cmax), can identify the factors that control the evolution of highly mature organic matter. The main factor for source rocks deposited in a weakly saline environment is the maturity, but for a highly saline environment both the maturity and salinity are key factors. The high salinity inhibits the molecular polymerization of organic matter and extends the oil generation peak. Given the differences in the bio-precursors in saline source rocks, we propose a new model for hydrocarbon generation that can be used to determine the oil generation potential of highly mature organic matter.

关键词： Negative ion ESI-FT-ICR-MS N-containing compound Residual hydrocarbon generation potential Highly mature organic matter Deep oil-gas Junggar Basin

Peroxidase-like active Cu-ZIF-8 with rich copper(I)-nitrogen sites for excellent antibacterial performances toward drug-resistant bacteria

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Nano Research 2024年第8期17卷 7427-7435页

作者： Xiaoze Wang Hui Wang jingkun zhang Ning Han Wenjun Ma Donghai zhang Mingshui Yao Xianliang Wang Yunfa Chen State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of the Chinese Academy of Sciences Beijing 100049China Laboratory of Theoretical and Computational Nanoscience CAS Key Laboratory of Nanosystem and Hierarchial FabricationCAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China China CDC Key Laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijing 100021China

Bacterial pathogens pose a serious threat to human health,and there is an urgent need to develop highly effective antibacterial materials to eliminate the increasingly serious contamination of drug-resistant ***,a Cu-doped ZIF-8 particle with unsaturated copper exhibits high peroxidase-like activity.99.998%antibacterial efficiency against *** can be achieved for 30 min at a low concentration of 50μg·mL^(−1),as well as complete sterilization against ***(up to 8 log).99.999%antibacterial efficiency against Methicillin-resistant Staphylococcus aureus can be achieved,performing orders of magnitude higher than *** mechanism shows that the unsaturated Cu-Nx sites are enzyme-like active centers,which could promote the consumption of bacteria reducing substances by H_(2)O_(2),and the generated*OH further aggravates bacterial oxidative stress and membrane *** importantly,the oxidation activity of adsorbed oxygen species on Cu-ZIF-8 is enhanced by charge transfer and structural changes between the ligand and copper center like natural ***-doped ZIF-8 with peroxidase-like activity shows great potential in antibacterial application and the revealed catalytic mechanism is helpful for understanding the high antibacterial activity of nanoparticles with Cu-Nx sites.

关键词： Cu-doped ZIF-8 peroxidase-like reactive oxygen species(ROS) catalytic mechanism antibacterial activity

Yanshanian–Himalayan geodynamic transformation of the northwestern Junggar Basin, southwestern Central Asian Orogenic Belt (CAOB), and its significance for petroleum accumulation

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Geoscience Frontiers 2023年第4期14卷 220-229页

作者： Dongming Zhi jingkun zhang Tao Wu Anbin Wu Yong Tang Yin Liu Jian Cao PetroChina Tuha Oilfield Company Hami 839000China School of Earth Sciences and Engineering Nanjing UniversityNanjing 210023China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China PetroChina Xinjiang Oilfield Company Karamay 843000China School of Geosciences China University of Petroleum(East China)Qingdao 266580China

The northwestern Junggar Basin in the southwestern Central Asian Orogenic Belt is a typical petroliferous *** widely distributed reservoirs in Jurassic–Cretaceous strata indicate that the region records Yanshanian–Himalayan tectonic activity,which affected the accumulation and distribution of *** mechanism of this effect,however,has not been fully *** fill the knowledge gap,we studied the structural geology and geochemistry of the well-exposed Wuerhe bitumen *** results indi-cate that deformation and hydrocarbon accumulation in the northwestern Junggar Basin during the Yanshanian–Himalayan geodynamic transformation involved two main *** the Yanshanian orogeny,a high-angle extensional fault system formed in Jurassic–Cretaceous strata at intermediate to shallow depths owing to dextral shear deformation in the orogenic *** fault system connected at depth with the Permian–Triassic oil–gas system,resulting in oil ascending to form fault-controlled reservoirs(e.g.,a veined bitumen deposit).During the Himalayan orogeny,this fault system was deacti-vated owing to sinistral shear caused by far-field stress related to uplift of the Tibetan *** and the reservoir densification caused by cementation formed favorable hydrocarbon preservation and accu-mulation ***,the secondary oil reservoirs that formed during the Yanshanian–Himalayan tectonic transformation and the primary oil reservoirs that formed during Hercynian–Indosinian orogenies form a total and complex petroleum system comprising conventional and uncon-ventional petroleum *** might be a common feature of oil–gas accumulation in the Central Asian Orogenic Belt and highlights the potential for petroleum exploration at intermediate–shal-low depths.

关键词： Geodynamic transformation Tectonic far-field stress Yanshanian-Himalayan Central Asian Orogenic Belt Total petroleum system

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上覆荷载对浅埋地下结构抗震性能的影响

振动与冲击 2023年第10期42卷 263-272页

作者：张静堃于仲洋张鸿儒张泽北京交通大学土木建筑工程学院北京100044 北京交通大学城市地下工程教育部重点实验室北京100044 中建二局第一建筑工程有限公司北京100176

保障地下结构具备足够的抗震性能对于降低结构损伤和提升灾后恢复效率均具有重要意义。为此,利用静-动力耦合的非线性数值分析方法,对不同上覆荷载作用下典型地铁车站的塑性铰发展特性及承重构件截面的弯曲延性需求进行了分析。研究表明... 详细信息

保障地下结构具备足够的抗震性能对于降低结构损伤和提升灾后恢复效率均具有重要意义。为此,利用静-动力耦合的非线性数值分析方法,对不同上覆荷载作用下典型地铁车站的塑性铰发展特性及承重构件截面的弯曲延性需求进行了分析。研究表明:地震作用下弯曲塑性铰首先出现在中柱端部,高轴压比极大削弱了中柱的抗震性能并导致结构整体水平变形能力劣化;结构上覆荷载条件对中柱截面曲率延性系数的影响显著,但对侧墙的影响较为有限;车站承重构件截面延性系数与层间位移角的关系可采用二次多项式函数描述,给出的相应拟合关系式可为抗震设计中构件截面延性比需求的评估提供相关参考。

关键词：轴压比地下结构抗震性能地震损伤破坏动力有限元分析

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数字经济、乡村振兴与共同富裕

统计与决策 2023年第20期39卷 11-16页

作者：张静坤张旺西京学院会计学院西安710123 西北大学经济管理学院西安710127

文章基于2011—2020年中国30个省份的面板数据,将数字经济、乡村振兴与共同富裕纳入统一框架,实证检验数字经济、乡村振兴对共同富裕的影响机制。结果显示:数字经济不仅可以直接促进共同富裕,而且还可以通过影响乡村振兴这一中介变量间... 详细信息

文章基于2011—2020年中国30个省份的面板数据,将数字经济、乡村振兴与共同富裕纳入统一框架,实证检验数字经济、乡村振兴对共同富裕的影响机制。结果显示:数字经济不仅可以直接促进共同富裕,而且还可以通过影响乡村振兴这一中介变量间接促进共同富裕。数字经济直接促进共同富裕时具有非线性效应,这种非线性效应在乡村振兴中介变量调节后依然存在。

关键词：数字经济乡村振兴共同富裕影响机制

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中国式现代化共同富裕的时空分异特征及推进路径

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中国软科学 2023年第1期 171-185页

作者：张旺白永秀张静坤西北大学经济管理学院陕西西安710127 西京学院会计学院陕西西安710123

中国式现代化共同富裕=共建富裕+共享富裕+共生富裕,共建富裕意味着大家一起奋斗勤劳致富,共享富裕意味着贫富差距缩小,共生富裕意味着人与自然和谐共生,共生富裕是可持续地共建富裕和共享富裕的前提条件。在此基础上,重塑中国式现代化... 详细信息

中国式现代化共同富裕=共建富裕+共享富裕+共生富裕,共建富裕意味着大家一起奋斗勤劳致富,共享富裕意味着贫富差距缩小,共生富裕意味着人与自然和谐共生,共生富裕是可持续地共建富裕和共享富裕的前提条件。在此基础上,重塑中国式现代化共同富裕指标体系,廓清时空分异特征,提炼推进路径。研究发现:中国式现代化共同富裕水平整体上偏低但呈递增态势,区域间差异是区域差异的主要来源,空间相关性较弱;中国共产党探索共同富裕有始终创造条件和始终分阶段有重点地逐步推进两个历史经验,始终围绕“以人民为中心”理念推进,提炼出新征程上主要有党的领导、高质量发展、示范区建设和乡村全面振兴4条关键路径。

关键词：中国式现代化共同富裕时空分异推进路径