RESUMO
Local alignment is an important task in molecular biology to see if two sequences contain regions that are similar. The most popular approach to local alignment is the use of dynamic programming due to Smith and Waterman, but the alignment reported by the Smith-Waterman algorithm has some undesirable properties. The recent approach to fix these problems is to use the notion of normalized scores for local alignments by Arslan, Egecioglu and Pevzner. In this paper we consider the problem of finding all local alignments whose normalized scores are above a given threshold, and present a fast heuristic algorithm. Our algorithm is 180-330 times faster than Arslan et al.''s for sequences of length about 120 kbp and about 40-50 times faster for sequences of length about 30 kbp.
Assuntos
Biologia MolecularRESUMO
The frontal cephalometric analysis has not gained its importance in maxillofacial surgery compared to the lateral cephalometric analysis. In general, the frontal cephalometric analysis is practicable in providing an accurate measurement of the horizontal position and the width of maxilla, zygoma, and mandible. It also provides an assessment in the horizontal and vertical asymmetry of the face. With this knowledge, it is reasonable to regard the frontal cephalometric analysis as a valuable tool in making accurate diagnosis, planning of operation and evaluation of the results for sophisticated maxillofacial surgery. In addition, a recent development of computer software provides an extra benefit in diagnosing and performing surgery which has been frequently used in the dental field, in contrast to its limited application in the plastic surgery. The authors measured the frontal cephalometry of 115 patients who had maxillofacial surgery in our hospital from January 2000 to October 2002. The total 124 operative procedures for the patients are as follows: 58 was angle contouring; 22 zygomatic reduction; 16 genioplasty; 11 sagital split ramus osteotomy; 4 anterior segmental osteotomy; 10 distraction osteogenesis, and 6 was two-jaw surgery. The detailed procedure of the measurement is as follows: Digital scanning of cephalometric films; Presentation of the digital images on computer software (Vceph(R), CyberMed Inc. Korea); Registration of 43 anatomic landmarks such as zygomatic arch, gonion, antegonion, jugular process, and the automatic analysis with a custom-modified computer software with 27 items including midline analysis, facial width and height analysis, ratio analysis, symmetry analysis, and mandibular analysis. The analyzed data can be depicted as in the figure and chart. With above the mentioned automatic analysis, we found it to be effective, time-saving and accurate in the diagnosis of the facial asymmetry and estimation of the ratio of the facial bone. In this study, the authors have devised the frontal cephalometric analysis for the plastic and reconstructive maxillofacial surgery and its automatically analyzed measurements by using the computer software. This modified frontal cephalometric analysis has proved to be useful and efficient for diagnosis, operation planning and evaluation of the result in maxillofacial surgery.