Establishment of a 24-hour electrocardiogram recording system using a Holter recorder for miniature swine

A Holter recording system was established for the Göttingen miniature swine. For this purpose, we first developed a jacket to hold a Holter recording set, and subsequently determined a bipolar lead suitable for obtaining stable electrocardiogram (ECG) recording without artifacts. To make the jacket, we measured the lengths of eight sites of the body of 14 miniature swine. Several types of jackets were made and tested. We observed the behaviour of animals with these jackets by videotape recorder (VTR) recording. These observations permitted development of a jacket suitable for Holter recording. The jacket permits easy placement of the recorder, and long-term ECG recording can be performed without difficulty. In order to determine a suitable lead for long-term recording, we recorded ECGs from six adult miniature swine using three types of leads, the M-X, R-L and A-B leads. The R-L lead frequently exhibited baseline drift, and QRS complexes often disappeared in this lead due to low amplitude. ECG recording with the M-X and A-Bleads was of sufficient quality to permit analysis. This system is expected to be useful for further cardiovascular research in miniature swine.

Time-Resolved High-Resolution Electron Microscopy of Clusters, Surfaces, and Interfaces

Nanoscale materials show a variety of interesting physical and chemical properties. Since the properties are mostly determined by mesoscopic- and atomicscale areas of the materials, characterization of nanoscale materials at the atomic level is crucial for understanding the origin of their properties as well as for tailoring them to industrial needs. High-resolution electron microscopy (HREM) is an effective method to observe atomic structures in nanophase materials. The “structure-imaging technique,” originated by Ueda et al., and Cowley and Iijima, contributed much to the development of the method. Innovations are anticipated in (1) three-dimensional analysis of nanophase materials in real space, (2) observation of dynamic phenomena, and (3) extraction of compositional and physical information from nanometer-sized areas. Using the structure-imaging technique, one can observe directly nanometer-scale particles and defect structures such as voids and line and plane defects in crystals, including surfaces and interfaces. There were previously some limitations on the study of the dynamic process on the atomic level since images were captured on films. The recent development of high-sensitivity silicon-integrated-target-television (SIT-TV) cameras has initiated a new stage of HREM.Our time-resolved-high-resolution-electron-microscopy (TRHREM) system is composed of a 200-kV HREM (JEOL: JEM-2010) equipped with a high-sensitivity SIT-TV camera, various types of dedicated sample holders, an ultrahigh-vacuum (UHV) sample-preparation chamber, and a digital videotape recorder, as partly illustrated in Figure 5. The HREM images at 0.8–1.0-million magnification are recorded on the videotape recorder. In the U.S.-Japan TV system, one “frame image” of 1/30-s time resolution is composed of two interlaced “field images” of 1/60-s time resolution. The digital videotape recorder enables us to output the two “field images” separately from two frame memories.

Rotations and transformations in quasimelting

Morphological fluctuations of a quasimolten particle have been analyzed using high resolution electron microscopy (HREM) to determine the order and relative importance of rotations, translations and morphological transformations.Small gold particles evaporated onto a holey silicon monoxide support were examined in a conventional 300kV HREM at an electron beam flux of 25A/cm2. Single particles were observed over a period of time. The particle behavior was recorded in real time onto a Sony 8mm videotape recorder, at the rate of 30 frames per second, via a Gatan TV camera. The acquired images were further processed using SEMPER software on an Apollo workstation. The image frames were analyzed by employing a data reduction scheme. A basis set of good images were selected from the entire recording, and completely characterized on the lines of earlier workers. The set was found to consist of four distinct morphologies in various orientations. Samples of the morphologies isolated are shown in Fig. 1.