Stability and Hopf bifurcation of HIV-1 model with Holling II infection rate and immune delay
作者:
Liao, Maoxin;Liu, Yanjin* ;Liu, Shinan;Meyad, Ali M.
期刊:
Journal of Biological Dynamics ,2022年16(1):397-411 ISSN:1751-3758
通讯作者:
Liu, Yanjin
作者机构:
[Liu, Shinan; Liao, Maoxin; Liu, Yanjin] Univ South China, Sch Math & Phys, Hengyang, Peoples R China.;[Meyad, Ali M.] Southwestern Univ Finance & Econ, Sch Publ Finance & Taxat, Chengdu, Peoples R China.
通讯机构:
[Liu, Yanjin] U;Univ South China, Sch Math & Phys, Hengyang, Peoples R China.
关键词:
34K20;34K60;92B05;92D30;HIV-1 model;Hopf bifurcation;Stability;immune delay
摘要:
This paper aims to analyse stability and Hopf bifurcation of the HIV-1 model with immune delay under the functional response of the Holling II type. The global stability analysis has been considered by Lyapunov–LaSalle theorem. And stability and the sufficient condition for the existence of Hopf Bifurcation of the infected equilibrium of the HIV-1 model with immune response are also studied. Some numerical simulations verify the above results. Finally, we propose a novel three dimension system to the future study. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
语种:
英文
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The state-dependent impulsive control for a general predator-prey model
作者:
Zhu, Xiaoxiao;Wang, Huilan;Ouyang, Zigen
期刊:
Journal of Biological Dynamics ,2022年16(1):354-372 ISSN:1751-3758
通讯作者:
Zhu, X.
作者机构:
[Zhu, Xiaoxiao; Ouyang, Zigen; Wang, Huilan] Univ South China, Sch Math & Phys, Hengyang, Peoples R China.
通讯机构:
[Xiaoxiao Zhu; Huilan Wang; Zigen Ouyang] S;School of Mathematics and Physics, University of South China, Hengyang, People's Republic of China<&wdkj&>School of Mathematics and Physics, University of South China, Hengyang, People's Republic of China<&wdkj&>School of Mathematics and Physics, University of South China, Hengyang, People's Republic of China
关键词:
34A37;34C25;37N25;Poincaré map;State-dependent impulse;order-1 periodic solution;predator–prey model;successor function
摘要:
In this paper, a general predator–prey model with state-dependent impulse is considered. Based on the geometric analysis and Poincaré map or successor function, we construct three typical types of Bendixson domains to obtain some sufficient conditions for the existence of order-1 periodic solutions. At the same time, the existing domains are discussed with respect to the system parameters. Moreover, the Analogue of Poincaré Criterion is used to obtain the asymptotic stability of the periodic solutions. Finally, to illustrate the results, an example is presented and some numerical simulations are carried out. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
语种:
英文
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Speed determinacy of travelling waves for a three-component lattice Lotka-Volterra competition system
作者:
Tang, Y.;Pan, C.* ;Wang, H.* ;Ouyang, Z.*
期刊:
Journal of Biological Dynamics ,2022年16(1):340-353 ISSN:1751-3758
通讯作者:
Pan, C.;Wang, H.;Ouyang, Z.
作者机构:
[Pan, C.; Wang, H.; Tang, Y.; Ouyang, Z.; Pan, C] Univ South China, Sch Math & Phys, Hengyang, Peoples R China.
通讯机构:
[Pan, C; Wang, H; Ouyang, Z] U;Univ South China, Sch Math & Phys, Hengyang, Peoples R China.
关键词:
35B20;92D25;Lattice Lotka–Volterra system;Primary 35K57;invasion speed;speed selection;three species
摘要:
In this paper, the invasive speed selection of the monostable travelling wave for a three-component lattice Lotka–Volterra competition system is studied via the upper and lower solution method, as well as the comparison principle. By constructing several special upper and lower solutions, we establish sufficient conditions such that the linear or nonlinear selection is realized. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
语种:
英文
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Simulations of adaptive temperature control with self-focused hyperthermia system for tumor treatment
作者:
Hu, Jiwen;Ding, Yajun;Qian, Shengyou* ;Tang, Xiangde
期刊:
Ultrasonics ,2013年53(1):171-177 ISSN:0041-624X
通讯作者:
Qian, Shengyou
作者机构:
[Qian, Shengyou; Ding, Yajun; Hu, Jiwen] Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.;[Hu, Jiwen] Univ S China, Coll Math & Phys, Hengyang 421001, Peoples R China.;[Tang, Xiangde] Hengyang Normal Coll, Dept Math, Hengyang 421008, Peoples R China.
通讯机构:
[Qian, Shengyou] H;Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.
关键词:
Ultrasound hyperthermia;Simulation;Temperature control;Tumor treatment
摘要:
The control problem in ultrasound therapy is to destroy the tumor tissue while not harming the intervening healthy tissue with a desired temperature elevation. The objective of this research is to present a robust and feasible method to control the temperature distribution and the temperature elevation in treatment region within the prescribed time, which can improve the curative effect and decrease the treatment time for heating large tumor (>= 2.0 cm in diameter). An adaptive self-tuning-regulator (STR) controller has been introduced into this control method by adding a time factor with a recursive algorithm, and the speed of sound and absorption coefficient of the medium is considered as a function of temperature during heating. The presented control method is tested for a self-focused concave spherical transducer (0.5 MHz, 9 cm aperture, 8.0 cm focal length) through numerical simulations with three control temperatures of 43 degrees C, 50 degrees C and 55 degrees C. The results suggest that this control system has adaptive ability for variable parameters and has a rapid response to the temperature and acoustic power output in the prescribed time for the hyperthermia interest. There is no overshoot during temperature elevation and no oscillation after reaching the desired temperatures. It is found that the same results can be obtained for different frequencies and temperature elevations. This method can obtain an ellipsoid-shaped ablation region, which is meaningful for the treatment of large tumor. (C) 2012 Elsevier B.V. All rights reserved.
语种:
英文
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组织细胞DNA降解与死亡时间的相关性的显微拉曼光谱分析
作者:
Xiong Ping;Guo Ping* ;Zhang Jing
期刊:
光谱学与光谱分析 ,2010年30(6):1511-1515 ISSN:1000-0593
通讯作者:
Guo Ping
作者机构:
[Xiong Ping; Zhang Jing] Univ S China, Sch Med, Dept Forens Med, Hengyang 421001, Peoples R China.;[Guo Ping] Univ S China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构:
[Guo Ping] U;Univ S China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词:
显微拉曼光谱;DNA降解;死亡时间间隔(PMI);相对峰强
摘要:
为了给死亡时间推断的研究提供新的途径与数据, 探讨了人死亡后组织细胞DNA含量变化与死后时间间隔关系. 将离体肾、肝组织置于特定环境中, 在不同时间点提取离体组织, 利用激光共焦显微拉曼光谱技术和统计学方法, 在拉曼位移测试范围内, 对死后不同时间肾、肝组织DNA含量变化进行拉曼光谱检测与统计学分析. 结果显示:人死亡后48~72 h, 随着死亡时间的推移, 肾、肝组织Raman光谱的主要散射峰峰位没有明显变化, 而其峰高有明显差异;所测组织的激光拉曼光谱特征峰的相对峰强值(I_(1094)/I_(2923))随死亡时间的推移而减小. 因此可以得出结论:人死亡后肾、肝组织细胞DNA含量随死亡时间延长呈下降趋势, 两者之间存在线性关系.
语种:
中文
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微血管中铁磁性药物微粒靶向聚集特性的研究
作者:
李新霞;郭萍;陈铀;熊平
期刊:
生物医学工程学杂志 ,2010年27(3):533-537 ISSN:1001-5515
通讯作者:
Li, X.
作者机构:
[李新霞; 郭萍] 南华大学,核科学技术学院,衡阳,421001;[李新霞] 南华大学,数理学院,衡阳,421001;[郭萍] 中南大学,信息物理工程学院,长沙,410083;[熊平] 中南大学;[陈铀] 南华大学
关键词:
放射性纳米铁核素;靶向治疗;收集率
摘要:
采用数值方法研究包裹有放射性纳米铁核素微粒的抗肿瘤药物在人体微血管中的输运和靶向聚集特征,分析药物在人体微血管中主要受到的外磁场吸引力和血流拖曳力的作用。研究结果表明,药物能够在病灶附近富集。另外,还分别研究了肿瘤的深度、药物中放射性纳米铁核素的含量、血流速度和血管的直径等对药物收集率的影响。
语种:
中文
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Research on adaptive temperature control in sound field induced by self-focused concave spherical transducer
作者:
Hu, Jiwen;Qian, Shengyou* ;Ding, Yajun
期刊:
Ultrasonics ,2010年50(6):628-633 ISSN:0041-624X
通讯作者:
Qian, Shengyou
作者机构:
[Qian, Shengyou; Ding, Yajun; Hu, Jiwen] Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.;[Hu, Jiwen] Univ S China, Coll Math & Phys, Hengyang 421001, Peoples R China.
通讯机构:
[Qian, Shengyou] H;Hunan Normal Univ, Coll Phys & Informat Sci, Changsha 410081, Hunan, Peoples R China.
关键词:
Self-focused concave source;Temperature control;Tumor therapy
摘要:
Temperature control of hyperthermia treatments is generally implemented with multipoint feedback system comprised of phased-array transducer, which is complicated and high cost. Our simulations to the acoustic field induced by a self-focused concave spherical transducer (0.5 MHz, 9 cm aperture width, 8.0 cm focal length) show that the distribution of temperature can keep the same "cigar shape" in the focal region during ultrasound insonation. Based on the characteristic of the temperature change, a two-dimensional model of a "cigar shape" tumor is designed and tested through numerical simulation. One single-point on the border of the "cigar shape" tumor is selected as the control target and is controlled at the temperature of 43 °C by using a self-tuning regulator (STR). Considering the nonlinear effects of biological medium, an accurate state-space model obtained via the finite Fourier integral transformation to the bioheat equation is presented and used for calculating temperature. Computer simulations were performed with the perfusion rates of 2.0 kg/(m<sup>3</sup> s) and 4.5 kg/(m<sup>3</sup> s) to the different targets, it was found that the temperatures on the border of the "cigar shape" tumor can achieve the desired temperature of 43 °C by control of one single-point. A larger perfusion rate requires a higher power output to obtain the same temperature elevation under the same insonation time and needs a higher cost for compensating the energy loss carried away by blood flow after steady state. The power output increases with the controlled region while achieving the same temperature at the same time. Especially, there is no overshoot during temperature elevation and no oscillation after steady state. The simulation results demonstrate that the proposed approach may offers a way for obtaining a single-point, low-cost hyperthermia system. ©2010 Elsevier B.V. All rights reserved.
语种:
英文
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Synthesis and antifungal activities of novel 5-amino-6-arylamino1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives
作者:
Wang, Hong-Qing* ;Zhou, Wei-Pimg;Wang, Yu-Yuan;Lin, Can-Rong
期刊:
Journal of Agricultural and Food Chemistry ,2008年56(16):7321-7325 ISSN:0021-8561
通讯作者:
Wang, Hong-Qing
作者机构:
[Wang, Yu-Yuan; Wang, Hong-Qing; Lin, Can-Rong] Univ S China, Coll Chem & Chem Engn, Hengyang 421001, Hunan, Peoples R China.;[Zhou, Wei-Pimg] Univ S China, Coll Math & Phys, Hengyang 421001, Hunan, Peoples R China.;[Wang, Hong-Qing] Univ S China, Coll Chem & Chem Engn, 28 Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
通讯机构:
[Wang, Hong-Qing] U;Univ S China, Coll Chem & Chem Engn, 28 Changsheng Rd, Hengyang 421001, Hunan, Peoples R China.
关键词:
1H-Pyrazolo[3,4-d]pyrimidin-4(5H)-one;aza-Wittig reaction;synthesis;1,8-2H-pyrazolo[3,4-d][1,2,4]triazolo[1,5-a]pyrimidin-4-one;antifungal
摘要:
A novel approach was developed to regioselectively synthesize new 5-amino-6-arylamino-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one 5 derivatives via a tandem aza-Wittig and annulation reactions of iminophosphorane 2, aromatic isocyanates, and hydrazine in 52-92% isolated yields. The compounds 5 reacted with triethyl orthoformate to give 1,8-2H-pyrazolo[3,4-d][1,2,4]triazolo[1,5-a] pyrimidin-4-ones 6 in good yields (62-94%). Their structures were clearly confirmed by spectroscopy data (IR, 1H NMR, MS), elemental analysis, or X-ray diffraction crystallography. The results of preliminary bioassay indicated that the compounds 5 and 6 possessed high antifungal activity against Botrytis cinerea Pers and Sclerotinia sclerotiorum. Compounds 5 showed much better antifungal activities when R was Me instead of PhCH2. Especially, compounds 6c, 6g, and 6i inhibited Sclerotinia by 100% at the concentration of 50 mg/L and by 83, 83, and 82% at the dosage of 10 mg/L, respectively. © 2008 American Chemical Society.
语种:
英文
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Impact of delays in cell infection and virus production on HIV-1 dynamics
作者:
Zhu, Huiyan;Zou, Xingfu
期刊:
Mathematical Medicine and Biology: A Journal of the IMA ,2008年25(2):99-112 ISSN:1477-8599
通讯作者:
Zhu, HY
作者机构:
[Zhu, Huiyan] Nanhua Univ, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.;[Zou, Xingfu] Univ Western Ontario, Dept Appl Math, London, ON N6A 5B7, Canada.
通讯机构:
[Zhu, HY ] ;Nanhua Univ, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.
关键词:
HIV-1;cells;virus;delays;stability
摘要:
Analysed is a mathematical model for HIV-1 infection with two delays accounting, respectively, for (i) a latent period between the time target cells are contacted by the virus particles and the time the virions enter the cells and (ii) a virus production period for new virions to be produced within and released from the infected cells. For this model, the basic reproduction number R0 is identified and its threshold property is discussed: the uninfected steady state is proved to be globally asymptotically stable if R0 < 1 and unstable if R0 > 1. In the latter case, an infected steady state occurs and is proved to be locally asymptotically stable. The formula for R0 shows that increasing either of the two delays will decrease R0. This may suggest a new direction for new drugs that can prolong the latent period and/or slow down the virus production process. © The author 2008. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.
语种:
英文
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异体皮质骨板不同固定方式的生物力学比较
作者:
张仁明;廖瑛;李宝兴;李朝旭;肖新跃;...
期刊:
中国修复重建外科杂志 ,2007年21(8):793-796 ISSN:1002-1892
通讯作者:
Zhang, R.
作者机构:
南华大学附属第一医院骨科;[李宝兴] 山西奥瑞生物有限公司;南华大学力学实验室;南华大学力学实验室 湖南衡阳;421001 怀化市第三人民医院骨科
关键词:
同种异体骨板;生物力学;固定方式
摘要:
目的 探讨异体皮质骨板采用不同固定方式的强度差异及机制.方法 由南华大学解剖室提供的14具(男8具,女6具)尸体上取下股骨27根,X线排除骨病后,用游标卡尺测量,取各骨最细部分的直径,制作27个不稳定骨折模型,随机分成A、B、C组,每组9个,分别采用3种方式固定:A组:用2块大小为110 mm×10 mm×3 mm异体皮质骨板嵌合固定;B组:用2块110 mm×10 mm×3 mm异体皮质骨板和5枚骨螺钉固定;C组:用1块110 mm×10 mm×3 mm骨板和5枚骨螺钉固定.分别进行生物力学实验,测试其压缩、弯曲及扭转刚度和极限载荷. 结果 不同固定方式显示不同的力学特征.A组的轴向刚度与B组相似,且高于C组,但抗弯和扭转刚度显著高于B、 C两组,差异有统计学意义(P<0.05).A组的压缩、弯曲、扭转极限载荷分别为1.65±0.34 kN,554.33±49.34 N,7.78±0.82 Nm;B组分别为1.12±0.37 kN,428.00±37.40 N,3.39±0.22 Nm,两组比较有统计学意义(P<0.05),而C组分别为0.71±0.46 kN,218.67±36.53 N,1.74±0.12 Nm,与A组比较差异有统计学意义(P<0.01). 结论 异体皮质骨板固定的强度与固定方式有关.双板嵌合固定比骨板骨螺钉固定具有更大的强度和刚度,可满足临床需要.
语种:
中文
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DNA solution of a graph coloring problem
作者:
Liu, YC* ;Xu, J;Pan, LQ;Wang, SY
期刊:
Journal of Chemical Information and Modeling ,2002年42(3):524-528 ISSN:1549-9596
通讯作者:
Liu, YC
作者机构:
[Liu, YC] Nanhua Univ Hengyang, Dept Math & Phys Sci, Hunan 421001, Peoples R China.;Huazhong Univ Sci & Technol, Dept Control Sci & Engn, Wuhan 430074, Peoples R China.
通讯机构:
[Liu, YC] N;Nanhua Univ Hengyang, Dept Math & Phys Sci, Hunan 421001, Peoples R China.
摘要:
The graph-theoretic parameter that bas probably received the most attention over the years is the chromatic number. As is well-Known, the coloring problem is an NP-Complete problem. In this paper, it has been solved by means of molecular biology techniques. The algorithm is highly parallel and has satisfactory fidelity. This work shows further evidence for the ability of DNA computing to solve NP-Complete problems.
语种:
英文
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草乌的拉曼光谱分析
作者:
Xiong, P* ;Guo, P;Zhou, Q
期刊:
光谱学与光谱分析 ,2002年22(3):417-418 ISSN:1000-0593
通讯作者:
Xiong, P
作者机构:
[Xiong, P] Nanhua Univ, Coll Med, Dept Forens Med, Hengyang 421001, Peoples R China.;Nanhua Univ, Coll Math & Phys, Hengyang 421001, Peoples R China.;Tsing Hua Univ, Dept Chem, Beijing 100084, Peoples R China.
通讯机构:
[Xiong, P] N;Nanhua Univ, Coll Med, Dept Forens Med, Hengyang 421001, Peoples R China.
关键词:
草乌;拉曼光谱;中毒
摘要:
草乌是一种重要的药用和有毒植物之一。本文采用FT Raman光谱法定性分析了生、熟草乌的组成。结果显示 ,草乌因加工 (熟草乌 )和未加工 (生草乌 )其拉曼光谱有不同 ,造成这一现象的原因可能是由于生草乌加工泡制成熟草乌所致 ,即导致熟草乌的毒性低于生草乌。这将有助于生、熟草乌的质量控制与毒性分析。
语种:
中文
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Some notes on 2-D graphical representation of DNA sequence
作者:
Liu, YC* ;Guo, XF;Xu, J;Pan, LQ;Wang, SY
期刊:
Journal of Chemical Information and Modeling ,2002年42(3):529-533 ISSN:1549-9596
通讯作者:
Liu, YC
作者机构:
[Liu, YC] Nanhua Univ, Inst Engn & Technol, Dept Math & Phys Sci, Hengyang 421001, Hunan, Peoples R China.;Xinjiang Univ, Inst Math & Phys, Urumqi 830046, Xinjiang, Peoples R China.;Huazhong Univ Sci & Technol, Dept Control Sci & Engn, Wuhan 430074, Hubei, Peoples R China.
通讯机构:
[Liu, YC] N;Nanhua Univ, Inst Engn & Technol, Dept Math & Phys Sci, Hengyang 421001, Hunan, Peoples R China.
摘要:
Some 2-D and 3-D graphical representations of DNA sequences have been given by Nandy, Leong and Mogenthaler, and Randic et al., which give visual characterizations of DNA sequences. In this paper, we presented a novel graphical representation of DNA sequences by taking four special vectors in 2-D Cartesian coordinate system to represent the four nucleic acid bases in DNA sequences, so that a DNA sequence is denoted on a plane by a directed walk. It is shown that the new graphical representation of DNA sequences has lower or nondegeneracy.
语种:
英文
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乌头的傅里叶变换红外光谱分析
作者:
Guo, P* ;Xiong, P;Yuan, YL
期刊:
光谱学与光谱分析 ,2002年22(4):603-606 ISSN:1000-0593
通讯作者:
Guo, P
作者机构:
[Guo, P] Nanhua Univ, Sch Math & Phys, Hengyang 421001, Peoples R China.;Nanhua Univ, Dept Forens Med, Hengyang 421001, Peoples R China.;Nanhua Univ, Sch Chem & Chem Engn, Hengyang 421001, Peoples R China.
通讯机构:
[Guo, P] N;Nanhua Univ, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词:
乌头;傅里叶变换;红外光谱;法医学;中毒
摘要:
乌头是一种重要的药用和有毒植物之一.本文利用傅里叶变换红外(FTIR)光谱法定性分析了不同乌头的组成.结果表明:乌头因泡制加工后其红外光谱有不同,造成这一现象的原因可能是由于乌头加工泡制后,使得其成分和部分成分含量有所改变,导致其毒性低于生乌头的毒性.这将有助于对乌头的质量控制与毒性分析.该方法快速、准确、不破坏样品.
语种:
中文
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Photoacoustic spectra of the whole blood from leukemia patients
作者:
Guo, P* ;Liu, L;Liu, Q
期刊:
光谱学与光谱分析 ,2000年20(3):457-458 ISSN:1000-0593
通讯作者:
Guo, P
作者机构:
[Guo, P] Hengyang Med Coll, Hengyang 421001, Peoples R China.;Hunan Commun Hosp, Changsha 410006, Peoples R China.
通讯机构:
[Guo, P] H;Hengyang Med Coll, Hengyang 421001, Peoples R China.
关键词:
光声光谱;白血病;血液;诊断;分型
摘要:
利用光声光谱对不同类型的白血病患者和正常人的全血进行检测 ,发现白血病患者与正常人全血光谱图特征峰有明显差异 ,结果提示患者全血的光声光谱图可能对早期白血病诊断及白血病分型具有较大的临床意义。
语种:
中文
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Raman Spectra of the Serums from Cancerous Persons
作者:
Guo, P* ;Yi, GH;Xiong, P;Yuan, YL;Xie, Q;...
期刊:
光谱学与光谱分析 ,2000年20(6):844-846 ISSN:1000-0593
通讯作者:
Guo, P
作者机构:
[Guo, P] Hengyang Med Coll, Dept Phys, Henyang 421001, Peoples R China.;Hengyang Med Coll, Affiliate Hosp 1, Hengyang 421001, Peoples R China.;Xiangtan Univ, Dept Phys, Xiangtan 411105, Peoples R China.
通讯机构:
[Guo, P] H;Hengyang Med Coll, Dept Phys, Henyang 421001, Peoples R China.
会议名称:
第七届原子光谱分析学术报告会
会议时间:
2000-10-01
会议地点:
成都
会议论文集名称:
光谱学与光谱分析
关键词:
癌症患者;血清测试;激光拉曼光谱;光谱图
摘要:
按正常人和不同种类癌症患者进行分类 ,用激光拉曼光谱分别对正常人、鼻咽癌患者、肝癌患者和慢性白血病患者四类受试者的血清在 0~ 2 0 0 0cm-1范围内进行测试。结果表明 ,同类患者中不同受试者血清的激光拉曼光谱特征峰值大小虽然不同 ,但光谱图特征基本一致 ;不同种类癌症患者血清的激光拉曼光谱图存在较大差异 ;在各类癌症患者血清的激光拉曼光谱图特征峰附近 ,正常人血清均没有拉曼光谱特征峰。
语种:
中文
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