2005.12
About Instruments Today No. 149
Nano Imaging on Bio Structures
The Principles and Applications of High Speed High Resolution Phase Contract Radiology Based on Synchrotron X-Rays [ 下載 PDF ]
Yeu-Kuang Hwu, Tsung-Yeh Yang, Chang-Hai Wang, Yuan-Ting Shih, Jung Ho Je, Giorgio Margaritondo
Radiology is the oldest and by far the largest field of application of X-rays. In recent years, this domain has been literally revolutionized by the exploitation of the unique characteristics of synchrotron sources. The results are particularly spectacular when the high spatial coherence of the radiation is used for novel and powerful approaches to radiology. The results are very high quality microradiology and microtomograhy images and movies-taken with a limited X-ray dose-that find a variety of applications in materials science, biology and medical research.
The Principles and Applications of Ultraspatially- Resolved Fourier Transform Infrared Microspectroscopy [ 下載 PDF ]
Yao-Chang Lee, Ching-Iue Chen
The infrared microspectroscopy beamline at the National Synchrotron Radiation Research Center (NSRRC) has been adapted to provide intense collimated radiation for a mid-infrared microscope. Infrared microscope with high brightness synchrotron radiation has greatly improved the spatial resolution of this technique by allowing high quality spectra to be collected from samples whose size is approaching the diffraction limit for this wavelength of light, typical 8–10 µm. In this study, the infrared spectral images of colorectal tissue showed that the absorbance of amide bands for normal tissues was much lower than that of the malignant tissue. The decrease in absorbance of phosphate of DNA was found in malignant tissue.
Development of In Vivo Multiphoton Microscopy in Biomedical Research [ 下載 PDF ]
Feng-Chieh Li, Wei-Liang Chen, Chen-Yuan Dong
Compared to conventional microscopic imaging techniques, multiphoton microscopy are point like in excitation, and highly penetrative in nature. Since this technique does not require artificial sample preparation and causes relatively low sample photo damage, it is an ideal alternative for optical biopsy. In our laboratory, we have developed a dorsal skinfold imaging chamber using the biocompatible material 6AL/4V-TI ELI for in vivo investigation into living organisms. However, prior to conducting in vivo research, ex vivo studies on the tissue samples of interest need to be studied. In our lab, we are focusing on topics such as photo-aging, tissue engineering, and cornea structure. The combination of multiphoton microscopy, ex vivo tissue characterization and in vivo observation will enable us to study physiological processes in their natural state, leading to an improved understanding of biologically and medically related issues.
Imaging the Conformation Changes of Plasmid DNA Molecules in Aqueous Environment by Atomic Force Microscopy [ 下載 PDF ]
I-Ching Hsiao, Chi-Hung Lin
For the past two decades, more and more researchers, including engineers, chemists, and biologists, were interested in the studies about the applications of atomic force microscopy in their research fields due to its capabilities that can be operated in liquid phase and at a controlled temperature, and provide nano-scale image resolution. In this study, we have observed the conformations of plasmid DNA molecules deposited on Ni- and APTES-treated mica surfaces by AFM in liquid phase. Another interesting study was also carried out in this report that DNA molecules would exhibit different conformations, while they were pre-mixed with NiCl2 solution and APTES solution before depositing on fresh cleaved mica surfaces.
The Principles and Applications of Transmission X-Ray Microscopy [ 下載 PDF ]
Mau-Tsu Tang, Yen-Fang Song, Gung-Chian Yin, Jian-Hua Chen, Yi-Ming Chen, Fu-Rong Chen, Keng S. Liang
Due to the nature of high penetration depth, short wavelength and various contrast mechanisms of X-rays, the X-ray microscopy has been long expected a powerful imaging tool. It is, however, until the invention of modern highly brilliant synchrotron light sources, the X-ray microscopy has become practical. The newly constructed advanced transmission hard X-ray microscope at National Synchrotron Radiation Research Center operational in energy 8–11 keV, provides threedimensional images with spatial resolution 25–60 nm and with phase contrast capability for imaging light specimens. This article will introduce the optical principle of the X-ray microscopy. The performance of the NSRRC X-ray microscope will be presented in the article with examples.
Preparation and Microscopic Characterization of Metal Nanoparticle Arrays [ 下載 PDF ]
Shangjr Gwo, Meng-Hsien Lin
Formation of two-dimensional metal nanoparticle arrays on technologically relevant substrates is gaining more interest in nanotechnology due to its applications in nanocatalyst, chemical and biological sensing, and nanophotonics (plasmonics). In this article, we introduce physical and chemical routes to synthesize such nanoparticles on two-dimensional planes. We will introduce the new concept of quantum nucleation mechanism in the traditional method of physical vapor deposition. Moreover, we will show how to prepare such particles on substrates from monodispersed gold colloidal solutions using linking organosilane self-assembled monolayers (SAMs). In addition, we will show some representative microscopic studies of such arrays.
Dynamic Characteristics and Modal Analysis of an Opto-Mechanical Structure [ 下載 PDF ]
Yi-Cheng Chen, Liang-Kai Lee
Optical mechanisms must possess static and dynamic stability to maintain relative positions between optical components and to ensure the image qualities of optical systems. Based on finite element analyses, this study applies modal analyses to improve the rigidity of an opto-mechanical structure. Firstly, a swept sine vibration test is performed to study the dynamic characteristics and natural frequencies of the opto-mechanical structure. Then, a reliable finite element model is built, based on which finite element modal analyses are performed to improve design parameters. Finite element modal analyses of the main structure and the secondary mirror support beam are performed to improve their rigidity, respectively. Finally, feasible solutions are proposed to attain an increased natural frequency and improved rigidity.
An Introduction to the Principle of Atomic Force Microscope (II) [ 下載 PDF ]
Ming Yen Lin, Chia-Seng Chang, Wenlung Li
Atomic Force Microscope (AFM) has been widely used in the field of surface measurement. It is helpful for any of user, especially for most of users who are not familiar with the functions of AFM, to operate AFM properly if they understand more with the principle and characteristics of AFM. In this article, the principle of tapping mode, which is the most frequently used, is mainly introduced. An effective physic model of motion, experimental data and experiences on AFM measurement are used to describe the physic characteristics of cantilever tip motion, tip-sample interaction and the principle of tapping mode.
High Power Factor and High Efficiency Power Supply [ 下載 PDF ]
Tai-Shan Liao, Natchpong Hatti
High power and high voltage supplies are usually required in industry and medical equipments such as traffic lights, medical white LEDs lamps, piezo driving, spectral lamps, etc. However, they need more power factor technology to meet green power concept for saving power energy. We offer a simple, low cost and off-line design 200 W (200 V, 1 A) high power factor and high power switching power supply.
Blood Purification Techniques [ 下載 PDF ]
Yung-Sheng Lin
In human disease treatment, blood treatment has governed a considerable proportion in medicine behavior. With the development of medicine technology, the skill that human beings deal with the blood is getting more and more mature. It can be efficient and timesaving for the transfusion blood to recover from the unhealthy condition. This article provides an overview of the theory and status of the blood purification technology in recent times, containing plasmaphersis, cytaphersis and blood adsorption. The purpose of plasmapheresis is to remove pathogeny-contained plasma and keep blood cells recycling. The aim of cytaphersis is to eliminate pathogenic cells in blood, while blood adsorption is to discard pathogeny in blood by adsorption action. It hopes that the introduction by this article can equip readers with primary acknowledge of blood purification technology.
