冷冻聚焦离子束-扫描电镜成像技术研究进展

冷冻聚焦离子束-扫描电镜成像(Cryo-FIB-SEM)是一种新兴的成像检测技术, 在原位进行冷冻聚焦离子束切割和冷冻扫描电镜成像, 为研究天然含水状态下生物样品内部未被破坏的原始结构打开了一扇窗口。近年来, 该技术在生命科学领域的应用研究取得了一系列重要进展。该文对其在冷冻体积连续成像、冷冻光电关联成像、冷冻透射扫描成像、冷冻含水切片制备监控及冷冻扫描图像处理等方面的研究进展进行综述, 并展望了该技术在大体积生物样品三维原位成像研究领域的前沿性发展趋势, 以期推动Cryo-FIB-SEM技术在生物样品三维结构研究中的应用。     

新书推荐:<生物医学光子学进展>

生物医学光子学是近年来受到国际生物医学界和光子学界关注的一个热点。随着最近几年的发展 ,该学科已包括了光子学、电子学、计算机、生命科学、数学、物理等学科的交叉与融合。生物医学光子学的研究必将对人类生命科学的发展产生重大影响。本书是一部重要的学术研究参考书 ,书中收集了最近几年在美国、加拿大、澳大利亚、日本等国家华人学者的学术论文。例如 :数字射线照相术、组织光学成像技术与图像重建、大脑活动与功能的近红外光学成像、双光子成像技术在神经科学中的应用、基于绿色荧光蛋白的显微活体成像等都是目前该领域的最新…     

超分辨显微成像技术在活细胞成像中的应用与发展

超分辨显微成像技术（super-resolution microscopy，SRM）可以绕过光学衍射极限对成像分辨率的限制，让以前观察不到的纳米级结构实现可视化，这一重大研究进展推动了现代生命科学和生物医学研究的进步与发展. 细胞是生物体的基本组成单位，对活细胞内部的细微结构和动力学过程进行研究是掌握生命本质必不可少的途径. 但由于成像原理或条件的限制，早期的SRM技术在活细胞成像应用方面受到了不同程度的限制. 近几年来，随着SRM和相关技术的发展，SRM在活细胞成像研究中的应用也越来越多. 本文简要介绍目前常见的几种SRM技术的基本原理和特点，并在此基础上着重阐述它们在活细胞成像应用中所取得的最新研究进展和发展方向.     

基于全偏振成像的数字病理方法

数字病理技术能够对病理切片进行高分辨率数字化,并利用计算机和数据技术对数字化图像进行定量分析和特征识别,以便降低病理医师的工作强度,提高诊断客观性和准确性,实现病理辅助诊断.全偏振显微成像是正在迅速发展的一类成像技术,具有不依赖染色、不造成损伤、富含亚细胞超分辨微观结构特征信息等优点,可在不同解剖学层次和空间尺度针对生物医学样本的微观结构进行定量表征,或对生命过程进行原位、在体的动态观测,在临床病理诊断等领域已经展示出了十分诱人的应用潜力.本文从数字病理图像分析技术的概念和方法出发,简要介绍偏振成像方法以及基于偏振成像技术的数字病理图像分析方法的前瞻性研究成果,目的是展示偏振数字病理的概念、技术、方法和初步应用,并展望其潜在的应用前景和未来发展方向.     

转基因小鼠在现代生命科学中的应用

随着分子生物学的发展,转基因技术取得了巨大的进步,并且在现代生命科学中得到了广泛的应用.针对转基因技术在生物医学研究领域中的重要作用,结合近年来转基因技术及转基因动物的研究成果,着重介绍转基因小鼠的发展,转基因的方法及在医学中的应用,并对转基因小鼠在现代生命科学中的应用前景进行了展望.     

红外荧光素Alexa Fluor 647标记的2型腺相关病毒保持天然的感染活性

近年来红外荧光素的研发及相应的标记技术的进展在生物医学领域的研究中备受关注,通过与尖端仪器的结合在一系列生物样本的检测中得到广泛的应用. 然而,红外荧光标记技术在病毒感染生物学研究中的应用却少见报道.本文建立了Alexa Fluor 647（AF647）红外荧光素标记重组2型腺相关病毒（AAV2）的方法,并通过凝胶电泳的银染、红外荧光成像和透射电镜分析等手段,对标记病毒的结构和形态与未标记的病毒进行了细致的比较,同时进一步鉴定了其感染293T细胞后的转导活性.结果发现,AAV2在标记后的理化性质和感染活性均未发生改变. 应用狭缝印迹和激光共聚焦显微成像技术,分别对标记病毒的细胞摄取效率和在宿主细胞内的分布进行描述,为红外标记AAV2在研究中的应用提供了范例.AF647标记的 AAV2为腺相关病毒的感染动力学研究提供了新的手段,具有敏感度高、抗荧光漂白和低非特异干扰等优点,并且对直接有效地结合形态学分析和生化分子生物学检测,具有重要的应用价值.     

超声弹性成像技术在乳腺肿块诊断中的研究进展及应用

超声弹性成像技术(UE)是一种新的超声成像技术,能够根据组织硬度进行成像,估计出组织内部的弹性信息,从而反映它的结构特点,该技术较传统触诊检查更加客观,在乳腺肿块的鉴别诊断中有较高的价值,其临床应用广泛并且得到了快速的发展。现就国内外文献对UE技术的原理、图像分析方法、技术研究进展及其在乳腺肿块鉴别诊断中的应用进行综述。     

小动物活体成像技术的应用

小动物活体成像技术在国内外得到越来越多的普及应用,极大地促进了生命科学特别是肿瘤研究的发展。本文就小动物活体成像技术的原理、标记方法和实际应用做简单介绍。     

全内反射荧光显微术在活细胞单分子检测中的应用

全内反射荧光显微术(total internal reflection fluorescence microscopy,TIRFM)是一种灵敏、快速的单分子成像和检测技术,近年来得到迅猛发展。该技术已广泛应用于生命科学、化学、物理学等领域。本文综述了全内反射荧光显微术的原理及其在活细胞单分子检测中的应用,并对其发展前景进行了展望。     

傅立叶变换红外光谱在生命科学中的应用

主要综述了傅立叶变换红外光谱在生命科学中的广泛应用.阐述了傅立叶变换红外光谱在生物大分子中的吸收峰位置、振动方式以及谱带归属,介绍了傅立叶变换红外光谱目前在肿瘤方面的研究,为从分子的角度研究癌变机理,提供了重要依据.     

Enhanced Thermal Stability of W‐Ni‐Al2O3 Cermet‐Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors

Solar thermal technologies such as solar hot water and concentrated solar power trough systems rely on spectrally selective solar absorbers. These solar absorbers are designed to efficiently absorb the sunlight while suppressing re‐emission of infrared radiation at elevated temperatures. Efforts for the development of such solar absorbers must not only be devoted to their spectral selectivity but also to their thermal stability for high temperature applications. Here, selective solar absorbers based on two cermet layers are fabricated on mechanically polished stainless steel substrates using a magnetron sputtering technique. The targeted operating temperature is 500–600 °C. A detrimental change in the morphology, phase, and optical properties is observed if the cermet layers are deposited on a stainless steel substrate with a thin nickel adhesion layer, which is due to the diffusion of iron atoms from the stainless steel into the cermet layer forming a FeWO₄ phase. In order to improve thermal stability and reduce the infrared emittance, tungsten is found to be a good candidate for the infrared reflector layer due to its excellent thermal stability and low infrared emittance. A stable solar absorptance of ≈0.90 is demonstrated, with a total hemispherical emittance of 0.15 at 500 °C.     

Infrared thermal imaging associated with pain in laboratory animals

The science of animal welfare has evolved over the years, and recent scientific advances have enhanced our comprehension of the neurological, physiological, and ethological mechanisms of diverse animal species. Currently, the study of the affective states (emotions) of nonhuman animals is attracting great scientific interest focused primarily on negative experiences such as pain, fear, and suffering, which animals experience in different stages of their lives or during scientific research. Studies underway today seek to establish methods of evaluation that can accurately measure pain and then develop effective treatments for it, because the techniques available up to now are not sufficiently precise. One innovative technology that has recently been incorporated into veterinary medicine for the specific purpose of studying pain in animals is called infrared thermography (IRT), a technique that works by detecting and measuring levels of thermal radiation at different points on the body’s surface with high sensitivity. Changes in IRT images are associated mainly with blood perfusion, which is modulated by the mechanisms of vasodilatation and vasoconstriction. IRT is an efficient, noninvasive method for evaluating and controlling pain, two critical aspects of animal welfare in biomedical research. The aim of the present review is to compile and analyze studies of infrared thermographic changes associated with pain in laboratory research involving animals.     

Heating of tissues by microwaves: A model analysis

We consider the thermal response times for heating of tissue subject to nonionizing (microwave or infrared) radiation. The analysis is based on a dimensionless form of the bioheat equation. The thermal response is governed by two time constants: one(τ₁) pertains to heat convection by blood flow, and is of the order of 20–30 min for physiologically normal perfusion rates; the second (τ₂) characterizes heat conduction and varies as the square of a distance that characterizes the spatial extent of the heating. Two idealized cases are examined. The first is a tissue block with an insulated surface, subject to irradiation with an exponentially decreasing specific absorption rate, which models a large surface area of tissue exposed to microwaves. The second is a hemispherical region of tissue exposed at a spatially uniform specific absorption rate, which models localized exposure. In both cases, the steady-state temperature increase can be written as the product of the incident power density and an effective time constant τ_eff, which is defined for each geometry as an appropriate function of τ₁ and τ₂. In appropriate limits of the ratio of these time constants, the local temperature rise is dominated by conductive or convective heat transport. Predictions of the block model agree well with recent data for the thresholds for perception of warmth or pain from exposure to microwave energy. Using these concepts, we developed a thermal averaging time that might be used in standards for human exposure to microwave radiation, to limit the temperature rise in tissue from radiation by pulsed sources. We compare the ANSI exposure standards for microwaves and infrared laser radiation with respect to the maximal increase in tissue temperature that would be allowed at the maximal permissible exposures. A historical appendix presents the origin of the 6-min averaging time used in the microwave standard. Bioelectromagnetics 19:420–428, 1998. © 1998 Wiley-Liss, Inc.     

Use of thermography for quantitative studies of spatial and temporal variation of stomatal conductance over leaf surfaces

This paper describes a new approach to the calibration of thermal infrared measurements of leaf temperature for the estimation of stomatal conductance and illustrates its application to thermal imaging of plant leaves. The approach is based on a simple reformulation of the leaf energy balance equation that makes use of temperature measurements on reference surfaces of known conductance to water vapour. The use of reference surfaces is an alternative to the accurate measurement of all components of the leaf energy balance and is of potentially wide application in studies of stomatal behaviour. The resolution of the technique when applied to thermal images is evaluated and some results of using the approach in the laboratory for the study of stomatal behaviour in leaves of Phaseolus vulgaris L. are presented. Conductances calculated from infrared measurements were well correlated with estimates obtained using a diffusion porometer.     

Theory and performance of an infrared heater for ecosystem warming

In order to study the likely effects of global warming on future ecosystems, a method for applying a heating treatment to open-field plant canopies (i.e. a temperature free-air controlled enhancement (T-FACE) system) is needed which will warm vegetation as expected by the future climate. One method which shows promise is infrared heating, but a theory of operation is needed for predicting the performance of infrared heaters. Therefore, a theoretical equation was derived to predict the thermal radiation power required to warm a plant canopy per degree rise in temperature per unit of heated land area. Another equation was derived to predict the thermal radiation efficiency of an incoloy rod infrared heater as a function of wind speed. An actual infrared heater system was also assembled which utilized two infrared thermometers to measure the temperature of a heated plot and that of an adjacent reference plot and which used proportional–integrative–derivative control of the heater to maintain a constant temperature difference between the two plots. Provided that it was not operated too high above the canopy, the heater system was able to maintain a constant set-point difference very well. Furthermore, there was good agreement between the measured and theoretical unit thermal radiation power requirements when tested on a Sudan grass (Sorghum vulgare) canopy. One problem that has been identified for infrared heating of experimental plots is that the vapor pressure gradients (VPGs) from inside the leaves to the air outside would not be the same as would be expected if the warming were performed by heating the air everywhere (i.e. by global warming). Therefore, a theoretical equation was derived to compute how much water an infrared-warmed plant would lose in normal air compared with what it would have lost in air which had been warmed at constant relative humidity, as is predicted with global warming. On an hourly or daily basis, it proposed that this amount of water could be added back to plants using a drip irrigation system as a first-order correction to this VPG problem.     

The value of infrared thermography for research on mammals: previous applications and future directions

• 1 Infrared thermography (IRT) involves the precise measurement of infrared radiation which allows surface temperature to be determined according to simple physical laws. This review describes previous applications of IRT in studies of thermal physiology, veterinary diagnosis of disease or injury and population surveys on domestic and wild mammals.
• 2 IRT is a useful technique because it is non‐invasive and measurements can be made at distances of <1 m to examine specific sites of heat loss to >1000 m to count large mammals. Detailed measurements of surface temperature variation can be made where large numbers of temperature sensors would otherwise be required and where conventional solid sensors can give false readings on mammal coats. Studies need to take into account sources of error due to variation in emissivity, evaporative cooling and radiative heating of the coat.
• 3 Recent advances in thermal imaging technology have produced lightweight, portable systems that store digital images with high temperature and spatial resolution. For these reasons, there are many further opportunities for IRT in studies of captive and wild mammals.

     

艾灸足三里对人体上腹部红外热像的影响：随机对照交叉实验

通过交叉对照实验观察艾灸足三里对人体上腹部红外热像的影响以研究经穴的特异性。受试者为健康男性学生,共31人,平均年龄（23．7±1．7）岁。对受试者左右两侧的足三里或对照非穴点进行直接温和艾灸15min,在艾灸前、艾灸后即刻以及艾灸后120min内每隔40min进行红外热像观察。研究发现在艾灸后即刻,足三里组与对照非穴点组的上腹中部与右侧的温度差改变量存在组间统计学差异,该现象与艾灸足三里对人体的保健作用之间的关系值得进一步研究。     

Solar and Thermal Radiation-Modulation Materials for Building Applications

Regulation of solar and thermal radiation of building envelope shows huge energy-saving potentials. Existing reviews mainly focus on the materials with fixed solar and thermal optical properties. Although there are reviews reporting the materials with modulated optical properties (e.g., radiative cooling materials with modulating thermal emissivity while maintaining high solar reflectance), they merely focus on either solar or thermal radiation modulation, which can provide limited or even negative building energy savings and thus may mislead the researchers to design low energy-efficient materials in practice. To help gain a holistic understanding of the state-of-the-art solar and thermal radiation-modulation materials (STRMMs) and guide researchers to develop more effective STRMMs for maximum building energy savings, here the STRMMs are reviewed in three categories, solar radiation modulation, thermal radiation modulation, and synergetic solar and thermal radiation modulation. In the former two categories, only single solar or thermal optical property is modulated while in the third category both solar and thermal optical properties are modulated. For STRMMs in each category, their working principles, representative examples, potential applications and future perspectives are compared and elaborated.     

Biophysical basis of medical thermovision

Characteristics of the thermal relief of the human body are reviewed. It is shown that the usage of thermovision in medical diagnostics requires the simultaneous and compatible consideration in the research process of three components: the contribution of the object itself, the influence of the medium through which the infrared radiation passes and the instrumental parameters of the infrared imager registering this radiation.     

Biophysical basis of medical thermovision

Characteristics of the thermal relief of the human body are reviewed. It is shown that the usage of thermovision in medical diagnostics requires simultaneous and compatible consideration in the research process of three components: the contribution of the object itself, the influence of the medium through which the infrared radiation passes and the instrumental parameters of the infrared imager registering this radiation.