Detection of Listeria monocytogenes in Foods and Characterization by PFGE

The aims of the present study were to investigate the prevalence of Listeria monocytogenes in 1042 foods collected from different market to characterize the isolates by phenotypical and molecular methods. In particular, L. monocytogenes obtained from different types of foods such as RTE (kimbap), fish (smoked salmon and seasoned-dried slice fish) and meat (cut raw beef and pork) from 2009 to 2011, were used. Twelve samples (2.1%) were positive for L. monocytogenes. Detection rate of L. monocytogenes varied significantly by food type and ranged from 1.1% to 5.2%. Meat is the highest prevalence for L. monocytogenes (5.2%) followed by RTE (1.8%) and Fish (1.1%). Twelve isolates were also serotyped by the agglutination method. The most common serotypes detected in the 12 strains tested were 1/4b (75.0%), followed by 1/2a (16.7%), and 1/2b (8.3%). For this study, we used serotyping and detected 6 different virulence-associated genes (inlA, inlB, plcA, plcB, hlyA, and actA) and 16s rRNA using multiplex-PCR. PFGE was performed to determine genetic characterization of L. monocytogenes strains to define the genetic diversity.

Preliminary Results of the Ground-Based Orographic Snow Enhancement Experiment for the Easterly Cold Fog (Cloud) at Daegwallyeong during the 2006 Winter

The snow enhancement experiments, carried out by injecting AgI and water vapor into orographically enhanced clouds （fog）, have been conducted to confirm Li and Pitter＇s forced condensation process in a natural situation. Nine ground-based experiments have been conducted at Daegwallyeong in the Taebaek Mountains for the easterly foggy days from January-February 2006. We then obtained the optimized conditions for the Daegwallyeong region as follows： the small seeding rate （1.04 g min-1） of AgI for the easterly cold fog with the high humidity of Gangneung. Additional experiments are needed to statistically estimate the snowfall increment caused by the small AgI seeding into the orographical fog （cloud） over the Taeback Mountains.

Monitoring the Hepatitis A Virus in Oyster from Korea

Hepatitis A virus (HAV) causes many cases of oyster- or clam-associated gastroenteritis in various countries. HAV was detected on oyster by RT-PCR in 19.6% (11/56) in Korea. The percentages of HAV-positive samples in 2011 and 2012 were 27.6% and 11.1%, respectively. Phylogenetic analysis revealed that several nucleotide sequences highly similar to those of HAVs isolated in this study. Phylogenetic analysis of the coding regions of the viral protein VP4/VP2 revealed that all amplicons were classi?ed into IA genogroup. It will provide useful data that aids in our understanding circulating HAVs and may contribute to future control.

Human Rhinoviruses in Korean with Acute Low Respiratory Tract Infections

Human rhinovirus (HRV) must be viewed as a significant etiological agent of acute low respiratory tract infections (ALRIs) in infants and young children. The present study has been carried out to investigate the prevalence of recently identified respiratory viruses and determine the phylogenetic composition of HRV strains. In total, 923 nasopharyngeal aspirates (NPAs) collected from hospitalized patients with ALRIs between January and December 2010 (453 females and 470 males) at five referral hospitals in Seoul were tested for respiratory viruses. Viruses were detected by RT-PCR (Reverse transcription polymerase chain reaction) in 501 (54.3%) of the 923 positive samples obtained. Overall, HRV was detected in 7.9%, ADV in 10.2%, IFV in 21.9%, RSV in 3.6%, hMPV in 2.7%, HCoV in 2.5%, HEV in 1.6%, HBoV in 1.6%, and PIV in 2.4% of the samples. HRV infections occurred throughout the year, with peaks in January, May, July, and November of 2010. Phylogenetic analyses using the VP4/VP2 cording region showed that among the 27 isolates with HRV, 14 (52%) were infected with species A, 2 (7%) were infected with species B, and 11 (41%) were infected with the strains from HRV-C. HRV-C sequences are genetically distinct, sharing only 32% to 33% of their amino acids with HRV-A and HRV-B, while retaining 46% to 100% identity with each other. HRV-A, B, and C were co-circulating in children hospitalized with ALRIs in Korea in 2010. These findings indicated that HRV-C was the important causative agent of HRV associated with ALRIs.

On the Dynamical Analysis in Aftershock Networks

We investigate the dynamical behavior of aftershocks in earthquake networks, and the earthquake network calculated from a time series is constructed by contemplating cell resolution and temporal causality. We attempt to connect an earthquake network using relationship between one main earthquake and its aftershocks from seismic data of California. We mainly examine some topological properties of the earthquake such as the degree distribution, the characteristic path length, the clustering coefficient, and the global efficiency. Our result cannot presently determine the universal scaling exponents in statistical quantities, but the topological properties may be inferred to advance and improve by implementing the method and its technique of networks. Particularly, it may be dealt with a network issue of convenience and of importance in the case how large networks construct in time to proceed on earthquake systems.