大孔径静态干涉成象光谱仪中的横向剪切干涉仪

介绍大孔径静态干涉成象光谱仪的光学原理,分析基于Sagnac型横向剪切分束器的干涉系统设计方案,推导了理论和实际的光程差公式,讨论了几种具体的结构形式,总结了各自的优缺点。     

Speciation of metal(loid)s in environmental samples by X-ray absorption spectroscopy: A critical review

Element specificity is one of the key factors underlying the widespread use and acceptance of X-ray absorption spectroscopy (XAS) as a research tool in the environmental and geo-sciences. Independent of physical state (solid, liquid, gas), XAS analyses of metal(loid)s in complex environmental matrices over the past two decades have provided important information about speciation at environmentally relevant interfaces (e.g. solid–liquid) as well as in different media: plant tissues, rhizosphere, soils, sediments, ores, mineral process tailings, etc. Limited sample preparation requirements, the concomitant ability to preserve original physical and chemical states, and independence from crystallinity add to the advantages of using XAS in environmental investigations. Interpretations of XAS data are founded on sound physical and statistical models that can be applied to spectra of reference materials and mixed phases, respectively. For spectra collected directly from environmental matrices, abstract factor analysis and linear combination fitting provide the means to ascertain chemical, bonding, and crystalline states, and to extract quantitative information about their distribution within the data set. Through advances in optics, detectors, and data processing, X-ray fluorescence microprobes capable of focusing X-rays to micro- and nano-meter size have become competitive research venues for resolving the complexity of environmental samples at their inherent scale. The application of μ-XANES imaging, a new combinatorial approach of X-ray fluorescence spectrometry and XANES spectroscopy at the micron scale, is one of the latest technological advances allowing for lateral resolution of chemical states over wide areas due to vastly improved data processing and detector technology.     

Protease sensors for bioimaging

Optical imaging of specific molecular targets and pathways in vivo has recently become possible through continued developments in imaging equipment, reconstruction algorithms, and more importantly the availability of imaging reporter molecules. These reporter molecules encompass photoproteins expressed in vivo and exogenously administered probes detectable by fluorescence and/or bioluminescence imaging. One particularly enticing aspect of optical imaging is the ability to design activatible probes with inherent amplification. This review summarizes our experience in developing novel near-infrared fluorescent (NIRF) imaging agents that report on protease activities. These agents are designed to be biocompatible, highly activatible, and able to produce bright NIRF following protease cleavage.     

Recent developments in computer vision-based analytical chemistry: A tutorial review

Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed.     

短波近红外在体荧光分子成像技术最新进展

癌症的诊断迄今所依赖的主要是一些离体检测方法以及超声波、X射线透视、X射线CT、核磁共振成像和PET等影像学技术. 癌症的确诊则以肿瘤组织或病变细胞的形态和其它宏观特征为依据, 这往往是一个侵入性和耗时的过程, 不适于癌症的早期诊断. 这些影像学技术目前也大都难以发现分子水平上的问题. 因此, 迄今癌症的早期诊断仍然是医学界面临的一个空前挑战. 光学成像方法, 特别是荧光成像方法具有对人体无害、非侵入、高灵敏和可进行在体多目标成像的优点, 随着荧光指示物的不断拓展和检测方法的不断创新, 有望在分子和细胞水平上实现癌症的早期诊断. 本文重点介绍了几项有较重要价值及工作在短波近红外区域的在体荧光成像技术的新进展.     

Synthesis and characterization of a new lanthanide based MRI contrast agent,potential and versatile tracer for multimodal imaging

In the present work a modular pathway towards the synthesis of a new versatile MRI contrast agent is reported and its physico-chemical properties are described. Two different functional groups were attached on two arms of the gadolinium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA) in order to get a platform able to bind one probe designed to target specific biological marker and a fluorescent molecule likely to be used for optical imaging. The nuclear magnetic relaxation dispersion (NMRD) profile, the oxygen-17 relaxometric NMR study and stability assessment versus transmetalation of the Gd-complex show that this new contrast agent has a relaxivity and transmetalation stability similar to Gd–DOTA.     

Synthesis of gemini surfactants with twelve symmetric fluorine atoms and one singlet F MR signal as novel F MRI agents

A family of fluorinated gemini surfactants derived from perfluoropinacol has been synthesized as novel ¹⁹F magnetic resonance imaging (¹⁹F MRI) agents. These fluorinated surfactants with 12 symmetric fluorine atoms and one singlet ¹⁹F MR peak can be conveniently prepared from perfluoropinacol and oligo(ethylene glycols) on multi-gram scales. Solubility, hydrophilicity (log P), and critical micelle concentration (CMC) measurements of these fluorinated surfactants indicated that high aqueous solubility can be achieved by introducing oligo(ethylene glycols) with appropriate length into perfluoropinacol, i.e., manipulating the fluorine content (F%). One of these fluorinated surfactants with high aqueous solubility and excellent ¹⁹F MR properties has been identified by ¹⁹F MRI phantom experiments as a promising ¹⁹F MRI agent.