生物波特点的实验观察

以细菌是多细胞有机体的观点,实验观察群体细菌波动生长的特点,发现细菌节律性生长的自组织过程中表现出生物波的开放性、单向性、适应性、节律性、稳定性、趋化性及同步性等特点。关于这些特点的认识方式对生物波的研究有较大的理论和实用价值。     

生物电磁学研究进展

生物电磁学(Bioelectromagnetics)是一门关于电磁学与生物学、医学相互渗透的边缘交叉学科。工频电磁场与癌症,特别是儿童白血病发病率的关系、移动电话是否会促进肿瘤的发生、生物体对电磁场的响应、作用到生物体的电磁场剂量的确定方法、制定电磁环境安全卫生标准、地球电磁环境的变迁及其对生物进化的影响、生物体内电磁场及生物组织电磁性质的测定和电磁场在生物医学中的应用等等,都是生物电磁学研究的课题。生物电磁学就是研究从直流电到远红外的电场、磁场和电磁场与生物系统相互作用的科学。电磁波包括短波、高频波(例如X射线、γ射…     

用光声技术测量生物组织粘弹特性的研究

报道了一种用光声技术测量生物组织粘弹特性的新方法,即用脉冲激光在生物组织中激发出光声信号（应力波）,从光声信号的振幅弛豫特性曲线中测量出应力波的弛豫时间,根据粘弹性理论,该弛豫时间就等于生物组织的粘弹比.用该方法测量Kelvin-Voigt模型的模拟生物组织的粘弹比,测量结果与用流变仪测量的结果完全一致,符合率达到97%.进而用光声方法测量出Maxwell模型的生物组织的粘弹比.理论分析与实验结果都表明：该方法只与被测物的声阻抗有关,而与它的状态无关,因此可用于任意状态的生物组织粘弹特性的测量.光声测量方法具有实时、快速、测量灵敏度高和重复性好的优点,因此在生物医学领域具有潜在的应用前景.     

激光对生物组织热和热致机械损伤的物理分析

从物理学角度阐明激光照射生物组织时在组织中形成热源的微观机制,系统分析这一热源对生物组织所产生的正、反两方面的作用,并进行量化描述,其结果对揭示和理解激光照射生物组织时所产生的宏观效应以及激光医疗应用都有积极作用。     

生物诱导子调节植物组织次生代谢

论述了生物诱导子对植物组织次生代谢的调节作用,包括生物诱导子的作用机制、生物诱导子的来源和种类以及生物诱导子的应用。     

生物诱导子调节植物组织次生代谢的研究

论述了生物诱导子对植物组织次生代谢的调节作用,包括生物诱导子的作用机制、生物诱导子的来源和种类以及生物诱导子的应用     

波生坦对高原性肺水肿的治疗作用

目的:探讨波生坦对高原性肺动脉高压的治疗作用及其对NO的影响.方法:SD大鼠随机分为:正常组,安慰剂组和波生坦.除正常组外,其他组置于减压中,8h/d,持续6周.自第4周起,安慰剂组和波生坦组的大鼠在低压低氧前分别给与生理盐水或波生坦灌胃.测定各组大鼠的平均肺动压(mPAP)、右心室肥厚指数(RV/LV+S%)、肺系数;测定各组大鼠动脉血和肺组织中NO的含量以及肺组织中NOS的活性.结果:和正常组相比,安慰剂组大鼠的mPAP,RV/LV+S%和肺系数显著升高;波生坦能显著抑制RV/LV+S%和肺系数的升高,并使mPAP下降至正常组水平.安慰剂组大鼠动脉血及肺组织中NO的含量和肺组织中NOS的活性都明显降低于正常组;波生坦治疗组大鼠动脉血和肺组织中NO的含量以及肺组织中NOS的活性较安慰剂组都显著升高.结论:波生坦通过增加低压低氧大鼠体内NOS的活性和NO的含量,来发挥其治疗高原性肺水肿的作用.     

生物波频效应的信息生化理论探讨

本文简要介绍了生物波频效应的研究概况,通过引用有关文献和研究结果,运用有关生化信息原理初步分析探讨了生物波频效应研究的特点,提出了应用生物波频效应进行生化信息研究的观点,核心问题,有关设想及应用前景。     

电磁场曝露对生物组织电磁特性的影响

电磁辐射严重影响着人体的健康.电磁场生物效应的发生机制与电磁场本身的特性相关,同时也与生物组织在电磁场作用下电磁特性的改变密切相关.生物体内的信号分子、自由基以及磁颗粒等处于外加电磁场中时其电磁特性会发生变化,尤其是不同频率电磁场曝露作用下生物组织的导电、介电以及磁学等特性会有非常显著的区别.明确不同频率电磁场作用下生物组织电磁特性的变化规律是研究电磁场生物效应发生机制以及预防问题的关键.综述了近年来电磁场对于生物组织电磁特性影响的研究成果,并对未来的研究方向做了展望.     

低能离子束对微生物细胞的刻蚀与损伤研究

以耐辐射异常微球菌和大肠杆菌为试材,用显微扫描电镜（ＳＥＭ）和电子自旋共振（ＥＳＲ）波谱仪研究了２０ｋｅＶ的Ｎ＾＋离子注入对其细胞的作用。结果表明,Ｎ＾＋离子注入对两种微生物既存在着直接作用的刻蚀损伤又存在着能量沉积所产生自由基的间接作用;对细胞的直接刻蚀作用是导致ＤＮＡ损伤和生物诱变的主要原因,而自由基所引起的主要是ＤＮＡ以外生物大分子的损伤和细胞的膜脂过氧化。随着注入剂量增大,两种微生物细胞受     

Epsilon wave: A review of historical aspects

The epsilon wave of the electrocardiogram (ECG) together with fragmented QRS (fQRS), the terminal conduction delay, incomplete right bundle branch block (IRBBB) and complete/advanced RBBB (CRBBB) of peripheral origin are part of a spectrum of ventricular depolarization abnormalities of arrhythmogenic cardiomyopathy (AC). Although the epsilon wave is considered a major diagnostic criterion for AC since 2010 (AC Task Force Criteria), its diagnostic value is limited because it is a sign of the later stage of the disease. It would be more appropriate to say that the epsilon wave is a “hallmark” of AC, but is of low diagnostic sensitivity. Although the epsilon wave has high specificity for AC, it can be present in other pathological conditions. In this update we will cover the nomenclature, association with disease states and electrocardiographic aspects of the epsilon wave.     

Wave energy alters biodiversity by shaping intraspecific traits of a habitat-forming species

The role of habitat-forming species in promoting biodiversity is widely acknowledged to vary across environmental gradients according to the extent to which they modify resources and environmental conditions. Population- and individual-level traits of habitat-forming species that influence species interactions may vary across gradients, but the importance of this indirect effect of environmental context is seldom considered. Here, we conducted surveys and field experiments to partition the effects of wave exposure on habitat-provisioning for invertebrates by oysters into direct and indirect effects, arising from morphological variation of the oysters. A survey of nine sites with varying degrees of wave exposure in Port Jackson, Australia revealed a decline in oyster densities and surface area as wave energy increased. Correlated to declining oyster surface area was a decrease in the richness and abundance of associated invertebrates. By contrast, taxon diversity increased with increasing wave energy. Experimental deployments of oysters at high and low wave energy sites confirmed that variations in oyster morphology was a phenotypically plastic response to environmental conditions. Oyster recruitment was also lower at high as compared to low wave energy sites, further contributing to the variation in oyster habitat among sites. A colonisation experiment in which exposed and sheltered morphologies of oysters were deployed under high and low wave energy conditions in a fully orthogonal design found that invertebrate communities were influenced by both the wave energy of sites and by habitat structure. Our study suggests that in some instances the indirect effects of environment on habitat availability, arising from changes in habitat-forming species density and morphology, may be as, or even more, important than the direct effects. Understanding how traits of habitat-forming species respond to environmental conditions, and how intraspecific trait-variation cascades to influence associated communities is critical to predicting when and where positive species interactions will be greatest.     

关于生物组织激光消融阈值的讨论

在激光医学领域,研究不同激光辐照参数对生物组织产生的效应是一个十分重要的课题,其中问题之一是实验研究各种组织的消融阈值。激光消融在临床医疗领域有着重要的应用前景。本文概述了消融阈值的物理含义,给出了消融阈值的定义,讨论了消融阈值与激光参数的关系。     

Calibration of the shear wave speed-stress relationship in ex vivo tendons

It has recently been shown that shear wave speed in tendons is directly dependent on axial stress. Hence, wave speed could be used to infer tendon load provided that the wave speed-stress relationship can be calibrated and remains robust across loading conditions. The purpose of this study was to investigate the effects of loading rate and fluid immersion on the wave speed-stress relationship in ex vivo tendons, and to assess potential calibration techniques. Tendon wave speed and axial stress were measured in 20 porcine digital flexor tendons during cyclic (0.5, 1.0 and 2.0 Hz) or static axial loading. Squared wave speed was highly correlated to stress (r²_avg = 0.98) and was insensitive to loading rate (p = 0.57). The constant of proportionality is the effective density, which reflects the density of the tendon tissue and additional effective mass added by the adjacent fluid. Effective densities of tendons vibrating in a saline bath averaged 1680 kg/m³ and added mass effects caused wave speeds to be 22% lower on average in a saline bath than in air. The root-mean-square error between predicted and measured stress was 0.67 MPa (6.7% of maximum stress) when using tendon-specific calibration parameters. These errors increased to 1.31 MPa (13.1% of maximum stress) when calibrating based on group-compiled data from ten tendons. These results support the feasibility of calculating absolute tendon stresses from wave speed squared based on linear calibration relationships.     

Dispersal and competition models for plants

New models for seed dispersal and competition between plant species are formulated and analyzed. The models are integrodifference equations, discrete in time and continuous in space, and have applications to annual and perennial species. The spread or invasion of a single plant species into a geographic region is investigated by studying the travelling wave solutions of these equations. Travelling wave solutions are shown to exist in the single-species models and are compared numerically. The asymptotic wave speed is calculated for various parameter values. The single-species integrodifference equations are extended to a model for two competing annual plants. Competition in the two-species model is based on a difference equation model developed by Pakes and Maller [26]. The two-species model with competition and dispersal yields a system of integrodifference equations. The effects of competition on the travelling wave solutions of invading plant species is investigated numerically.     

计算强激光作用下生物组织中烧蚀深度的新公式

本文采用强激光对生物组织热作用的一维Stefan数学模型和反问题辨识方法,并充分考虑实际多维问题的复杂性,提出了确定强激光作用下烧蚀深度的计算关系式。由该公式得出的理论计算结果与实验数据符合得较好。     

50Hz 1．8mT电磁场对成骨细胞增殖与分化成熟影响的波形比较研究

在50 Hz 1.8 mT的4种不同波形电磁场(electromagnetic fields,EMFs)中筛选促进体外培养大鼠成骨细胞(rat osteoblasts,ROB)增殖与分化成熟的最佳波形.体外分离培养大鼠颅骨成骨细胞,传代后随机分为5组,分别用频率50 Hz,EMFs强度为0 mT(对照组)和1.8 mT的正弦波、三角波、方波和锯齿波处理ROB,30 min/(次.天).在磁场处理后4～8天细胞呈现特征样分布.方波促进成骨细胞增殖,正弦波抑制成骨细胞增殖.三角波和正弦波增加ALP活性,其中ALP染色、茜素红钙化结节染色和胶原Ⅰ(collagen-Ⅰ)免疫组织化学检测结果与ALP活性一致.在EMFs处理后的24 h、96 h和72 h后EMFs分别提高Runx-2、Opg和Igf基因表达水平,其中尤以正弦波和三角波作用最为显著.上述结果表明:50 Hz 1.8 mT方波促进成骨细胞增殖,正弦波抑制成骨细胞增殖.50 Hz 1.8 mT EMFs能促进体外培养成骨细胞分化成熟,其中尤以正弦波和三角波促进成骨细胞分化成熟作用最为显著.     

Attraction and repulsion of spiral waves by inhomogeneity of conduction anisotropy—a model of spiral wave interaction with electrical remodeling of heart tissue

Various forms of heart disease are associated with remodeling of the heart muscle, which results in a perturbation of cell-to-cell electrical coupling. These perturbations may alter the trajectory of spiral wave drift in the heart muscle. We investigate the effect of spatially extended inhomogeneity of transverse cell coupling on the spiral wave trajectory using a simple active media model. The spiral wave was either attracted or repelled from the center of inhomogeneity as a function of cell excitability and gradient of the cell coupling. High levels of excitability resulted in an attraction of the wave to the center of inhomogeneity, whereas low levels resulted in an escape and termination of the spiral wave. The spiral wave drift velocity was related to the gradient of the coupling and the initial position of the wave. In a diseased heart, a region of altered transverse coupling corresponds with local gap junction remodeling that may be responsible for stabilization-destabilization of spiral waves and hence reflect potentially important targets in the treatment of heart arrhythmias.     

长波紫外线辐射对脊椎动物的影响

臭氧层空洞的加剧使紫外辐射不断加强,造成的环境污染已经成为广为关注的问题,但大多数都集中在中波紫外线(UVB)的生物学作用及其与两栖动物衰减关系的研究,有关长波紫外线(UVA)对生物体损伤作用的研究却甚少。本文综述了近年来UVA对脊椎动物损伤的研究概况,从细胞结构、酶活性、遗传物质、膜结构以及免疫系统等方面阐述了UVA的损伤机理,并对低剂量辐射诱导兴奋效应对紫外损伤的保护作用进行了简要概述。最后分析和总结了关于UVA损伤研究所存在的问题及两栖动物作为实验用动物模型在研究紫外线损伤中的作用。     

A device for reducing the effects of wave action in shallow water

A device, consisting of two sets of perforated baffles, was designed to mediate the effects of mechanical wave action during tidal flooding. The construction, set-up and effectiveness of this device are described.