Biomedical subjects

Liwei Peng

Publications and source records attributed to Liwei Peng.

3 recordsLinked to original sources

PubMed2006

EMAN2: an extensible image processing suite for electron microscopy.

EMAN is a scientific image processing package with a particular focus on single particle reconstruction from transmission electron microscopy (TEM) images. It was first released in 1999, and new versions have been released typically 2-3 times each year since that time. EMAN2 has been under development for the last two years, with a completely refactored image processing library, and a wide range of features to make it much more flexible and extensible than EMAN1. The user-level programs are better documented, more straightforward to use, and written in the Python scripting language, so advanced users can modify the programs' behavior without any recompilation. A completely rewritten 3D transformation class simplifies translation between Euler angle standards and symmetry conventions. The core C++ library has over 500 functions for image processing and associated tasks, and it is modular with introspection capabilities, so programmers can add new algorithms with minimal effort and programs can incorporate new capabilities automatically. Finally, a flexible new parallelism system has been designed to address the shortcomings in the rigid system in EMAN1.

Algorithms↗

PubMed2003

Object oriented database and electronic notebook for transmission electron microscopy.

As high-resolution biological transmission electron microscopy (TEM) has increased in popularity over recent years, the volume of data and number of projects underway has risen dramatically. A robust tool for effective data management is essential to efficiently process large data sets and extract maximum information from the available data. We present the Electron Microscopy Electronic Notebook (EMEN), a portable, object-oriented, web-based tool for TEM data archival and project management. EMEN has several unique features. First, the database is logically organized and annotated so multiple collaborators at different geographical locations can easily access and interpret the data without assistance. Second, the database was designed to provide flexibility to the user, so it can be used much as a lab notebook would be, while maintaining a structure suitable for data mining and direct interaction with data-processing software. Finally, as an object-oriented database, the database structure is dynamic and can be easily extended to incorporate information not defined in the original database specification.

Databases, Factual↗

PubMed2002

[Effect of Angiogenesis inhibitor (TNP-470) on the morphology of GNM cell line in vitro].

OBJECTIVE: The purpose of this study was to investigate the effect of an angiogenesis inhibitor (TNP-470) on the ultra micro-structural morphological changes of GNM cell line, which was derived from human oral squamous cell carcinomas in vitro. METHODS: The GNM cells were cultured and, the effect of TNP-470 on ultra micro-structural morphological changes of GNM cells was observed under the inverted microscope, the scanning electron microscope (SEM) and the transmission electron microscope (TEM). RESULTS: Numerous round cells, shrinkage of cellular membrane and dead cells were observed 48 hours after 2 micrograms/ml of TNP-470 was added into the GNM cellular suspension. After 72 hours, GNM cells became shortened and, the number of microvilli of the cellular surface was observed under the SEM and TEM. A large number of GNM cells turned into necrosis, accompanying with the destruction of mitochondria and endoplasmic reticula. CONCLUSION: TNP-470 has a strong tumor cytotoxic effect on GNM cells, which may be due to its destructibility on mitochondria and endoplasmic reticula of GNM cells. TNP-470 can alter the surface structure of GNM cell membrane, which suggests that TNP-470 may interrupt the metastasis of GNM cells.

Angiogenesis Inhibitors↗