Biomedical subjects

Jin Xu

Publications and source records attributed to Jin Xu.

97 records · Page 6Linked to original sources

PubMedDate not supplied

Some notes on 2-D graphical representation of DNA sequence.

Some 2-D and 3-D graphical representations of DNA sequences have been given by Nandy, Leong and Mogenthaler, and Randic et al., which give visual characterizations of DNA sequences. In this paper, we presented a novel graphical representation of DNA sequences by taking four special vectors in 2-D Cartesian coordinate system to represent the four nucleic acid bases in DNA sequences, so that a DNA sequence is denoted on a plane by a directed walk. It is shown that the new graphical representation of DNA sequences has lower or nondegeneracy.

DNA↗

PubMedDate not supplied

A Chinese Postman Problem based on DNA computing.

DNA computing is a novel method for solving a class of intractable computational problems, in which the computing can grow exponentially with the problem size. Up to now, many accomplishments have been achieved to improve its performance and increase its reliability. A Chinese Postman Problem has been solved by means of molecular biology techniques in the paper. A small graph was encoded in molecules of DNA, and the "operations" of the computation were performed with standard protocols and enzymes. This work represents further evidence for the ability of DNA computing to solve NP-complete search problems.

Base Sequence↗

PubMedDate not supplied

A DNA algorithm for the graph coloring problem.

A DNA algorithm based on surfaces for the graph coloring problem is presented. First the whole combinatorial color assignments to the vertices of a graph are synthesized and immobilized on a surface; then a vertex is legally colored while those adjacent to it with illegal colors are deleted; and the cycle is repeated until finally the correct color assignments to the graph are reached. Compared with the other DNA algorithms, our algorithm is easy to implement and error-resistant.

Algorithms↗

PubMedDate not supplied

DNA sequence design based on template strategy.

In DNA based computation and DNA nanotechnology, the design of proper DNA sequences has turned out to be an elementary problem. This paper takes a further look at the template strategy proposed in work by Frutos, A. G. et al. (Nucleic Acids Res. 1997, 25, 4748-4757). The H-measure proposed by Garzon et al. (Proceedings of the Second Annual Genetic Programming Conference, 1997; pp 472-487) is combined in this strategy to optimize the template and map sets obtained. Finally we describe a constructing method that can still produce more sequences by the results obtained in this paper.

Algorithms↗

PubMedDate not supplied

Solving the 3-SAT problem based on DNA computing.

The 3-SAT problem is an NP-complete problem, and many algorithms based on DNA computing have been proposed for solving it since Adleman's pioneering work. This paper presents a new algorithm based on the literal string strategy proposed by Sakamoto et al. Simulation results show that the maximal number of literal strings produced during the computing process is greatly reduced. Moreover, the length of the literal strings is also reduced from m to n at most.

Algorithms↗

PubMedDate not supplied

Hydrops fetalis secondary to parvovirus B19 infections.

BACKGROUND: Fetal infection by human parvovirus B19 is a common cause of fetal anemia, nonimmune hydrops fetalis, and spontaneous abortion and can result in fetal death. Recent improvements in diagnosing parvovirus infections and the availability of intrauterine transfusion have reduced the overall rate of fetal loss after maternal exposure. METHODS: We report two cases of maternal parvovirus infection with classic findings of hydrops fetalis and review various aspects of parvovirus infection with emphasis on the developing management options in pregnancy. RESULTS AND CONCLUSIONS: Different management led to different results. In the first case there was normal neonatal and infantile development, and in the second case, the fetus died. With accurate laboratory testing, obstetric sonography, and fetal transfusion, the fetal mortality from parvovirus infection has been reduced considerably, and most pregnancies complicated by maternal parvovirus infection result in healthy outcomes.

Adult↗

PubMedDate not supplied

Safety and immunogenicity of a combination measles, mumps, rubella and varicella vaccine (ProQuad).

BACKGROUND: A combination measles, mumps, rubella, and varicella vaccine (ProQuad, Merck & Co., Inc, West Point, PA) was evaluated in five clinical trials. Use of ProQuad would result in fewer injections for children and would facilitate universal immunization against all four diseases. OBJECTIVE: To describe the combined results obtained from the studies conducted during the clinical development program for ProQuad. METHODS: A total of 5833 healthy children, 12-23 months of age, and 399 healthy children, 4-6 years of age, received 1 or 2 doses of ProQuad in five controlled clinical trials. M-M-R II and VARIVAX were used as the control for most studies. Safety was evaluated for six weeks postvaccination and immunogenicity was assessed six weeks after each dose by a sensitive assay (ELISA or gpELISA). RESULTS: A single dose of ProQuad in 12- to 23-month-old children was shown to be as immunogenic as a single dose of M-M-R II and VARIVAX and was generally well tolerated. ProQuad can be used concomitantly with other vaccines (hepatitis B and Hoemophilus influenzoe b). A higher rate of fever was reported after 1 dose of ProQuad compared to M-M-R II and VARIVAX, but fever episodes were transient without long-term sequelae. Both a 2-dose regimen of ProQuad in 12- to 23-month-olds and use of ProQuad in place of M-M-R II at 4-6 years were shown to be immunogenic and well tolerated. The incidence of adverse experiences following a second dose of ProQuad was lower than that following the initial dose. CONCLUSIONS: A single dose of ProQuad is as immunogenic as M-M-R II and VARIVAX and is well tolerated in a 1- or 2-dose schedule. ProQuad should easily fit into the routine immunization schedule.

Antibodies, Viral↗