Pusan National University

About: Pusan National University is a education organization based out in Busan, South Korea. It is known for research contribution in the topics: Catalysis & Population. The organization has 24124 authors who have published 45054 publications receiving 819356 citations. The organization is also known as: Busan National University & Pusan University.

Soft network composite materials with deterministic and bio-inspired designs.

Abstract: Hard and soft structural composites found in biology provide inspiration for the design of advanced synthetic materials. Many examples of bio-inspired hard materials can be found in the literature; far less attention has been devoted to soft systems. Here we introduce deterministic routes to low-modulus thin film materials with stress/strain responses that can be tailored precisely to match the non-linear properties of biological tissues, with application opportunities that range from soft biomedical devices to constructs for tissue engineering. The approach combines a low-modulus matrix with an open, stretchable network as a structural reinforcement that can yield classes of composites with a wide range of desired mechanical responses, including anisotropic, spatially heterogeneous, hierarchical and self-similar designs. Demonstrative application examples in thin, skin-mounted electrophysiological sensors with mechanics precisely matched to the human epidermis and in soft, hydrogel-based vehicles for triggered drug release suggest their broad potential uses in biomedical devices.

Transverse momentum and centrality dependence of high-pT nonphotonic electron suppression in Au+Au collisions at sNN=200GeV

Abstract: The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of the inclusive yield of nonphotonic electrons, which arise dominantly from semileptonic decays of heavy flavor mesons, over a broad range of transverse momenta (1.2

Pandemic Spread of an O3:K6 Clone of Vibrio parahaemolyticus and Emergence of Related Strains Evidenced by Arbitrarily Primed PCR and toxRS Sequence Analyses

Abstract: Some strains of Vibrio parahaemolyticus, a marine bacterium, can cause gastroenteritis in humans through consumption of seafood. It was reported in the late 1960s that almost all clinical strains, but very few environmental strains, manifest Kanagawa phenomenon (KP), β-type hemolysis on Wagatsuma agar (8, 19). KP is caused by high-level production of thermostable direct hemolysin. Thermostable direct hemolysin is encoded by the tdh gene (13, 17), which was detected almost exclusively in clinical strains in an early study (11). The role of thermostable direct hemolysin in enterotoxigenicity was demonstrated by construction and examination of the tdh-deficient mutant of a KP-positive strain (10). Investigation of an outbreak in the Maldives in 1985 revealed that some clinical strains do not possess the tdh gene but carry the tdh-related hemolysin (trh) gene (14). The trh sequence was approximately 70% identical to the tdh sequence. There is much greater strain-to-strain divergence among trh sequences than among tdh sequences. The trh sequences in different strains, however, can be clustered into two groups represented by the trh1 and trh2 genes, which have 84% sequence identity (5). Strains possessing either the tdh gene, the trh gene, or both were shown to be strongly associated with gastroenteritis (5, 20). Surveillance for V. parahaemolyticus infection was initiated in January 1994 in Calcutta, India. A group of strains belonging to serovar O3:K6 and possessing the tdh gene but not the trh gene appeared suddenly in February 1996 and was shown to be responsible for the high incidence of V. parahaemolyticus infection since then in Calcutta (16). Serovar O3:K6 was not isolated before February 1996 in Calcutta. In addition, the O3:K6 strains isolated in Calcutta were shown to exhibit unique profiles in an arbitrarily primed PCR (AP-PCR) analysis (16). Strains belonging to the same group, i.e., O3:K6 strains possessing the tdh gene but not the trh gene and showing the unique AP-PCR profiles, were also detected among those isolated from travelers arriving in Japan from Southeast Asian countries from 1995 on (16). Thus, the Calcutta O3:K6 strains and the above strains from the travelers were considered to belong to a single clone (16). These results suggested that this unique clone, referred to below as a new O3:K6 clone, might have emerged recently and become prevalent not only in Calcutta, India, but also in other parts of the world. We examined this hypothesis, and we present evidence in this study for the first pandemicity in the history of V. parahaemolyticus. Clinical strains isolated over 22 years, starting from 1977, in a hospital in Bangladesh were available. The emergence of the new O3:K6 clone in 1996 but not earlier was demonstrated by examination of these strains. Next, we showed by AP-PCR analysis that the clinical strains of serovar O3:K6 isolated in six other countries, including the United States, from 1997 on belong to the same clone. We then developed a novel PCR method to identify the strains belonging to the new O3:K6 clone. We utilized the toxRS operon sequence to develop this PCR method. The toxR and toxS genes in the toxRS operon encode transmembrane proteins involved in the regulation of virulence-associated genes and are well conserved in the genus Vibrio (3, 7, 18; J. H. Rhee, S. E. Lee, S. Y. Kim, S. H. Shin, C. M. Kim, P. Y. Ryu, K. C. Leong, S. H. Choi, and S. S. Chung, Abstr. 98th Gen. Meet. Am. Soc. Microbiol., abstr. B-171, p. 84, 1998; V. Vuddhakul, T. Nakai, C. Matsumoto, T. Oh, T. Nishino, M. Nishibuchi, and J. Okuda, submitted for publication). We used the intraspecies variation of the toxRS sequence to develop a cluster-specific PCR method that allowed for confirmation of the clonality of the new O3:K6 strains. By using this PCR method in our investigation, we found emerging strains that were almost indistinguishable from the new O3:K6 clone, although the strains belonged to different serovars.