Biomedical subjects

Wooyoung Choi

Publications and source records attributed to Wooyoung Choi.

3 recordsLinked to original sources

PubMed2006

Acute hemorrhagic conjunctivitis epidemic caused by coxsackievirus A24 variants in Korea during 2002-2003.

A variant of coxsackievirus A24 (CA24v) is one of the agents causing acute hemorrhagic conjunctivitis. There was an epidemic of acute hemorrhagic conjunctivitis caused by CA24v in Korea from 2002 to 2003. Seventy-one strains of CA24v were isolated from 159 conjunctival specimens (45%). Most of the patients were school children under the age of 20. The epidemic began in the first week of August in 2002, and spread extensively, with a peak in the third week of September. CA24v strains were also isolated from conjunctival specimens in 2003. Reverse transcription polymerase chain reaction (RT-PCR) was performed and sequencing of the 340 bp fragment of the VP1 region of the viruses. Sequencing data were multiple-aligned using CLUSTAL W (version 1.81). Phylogenetic trees were plotted using TreeView (version 1.6.6). Homologies ranged from 97.7%-100%, depending on geographical regions: from 99.4%-100% in 2002 and 98.4%-100% in 2003. A phylogenetic tree based on the nucleotide sequence homologies formed clusters depending on years rather than on geographical regions. Identities (98%-100%) were found among the Korean CA24v strains, and there was 85%-90% homology between these and the prototype strain.

Adolescent↗

PubMed2004

Traveling waves in rotating Rayleigh-Bénard convection.

A combined analytical, numerical, and experimental study of the traveling-wave wall mode in rotating Rayleigh-Bénard convection is presented. No-slip top and bottom boundary conditions are used for the numerical computation of the linear stability, and the coefficients of the linear complex Ginzburg-Landau equation are then computed for various rotation rates. Numerical results for the no-slip boundary conditions are compared with free-slip calculations and with experimental data, and detailed comparison is made at a dimensionless rotation rate Omega=274. It is found that the inclusion of the more realistic no-slip boundary conditions for the top and bottom surfaces brings the numerical linear stability analysis into better agreement with the experimental data compared with results using free-slip top/bottom boundary conditions. Some remaining discrepancies may be accounted for by the finite conductivity of the sidewall boundaries.

Journal Article↗

PubMed2003

Strongly nonlinear long gravity waves in uniform shear flows.

Long surface gravity waves of finite amplitude in uniform shear flows are considered by using an asymptotic model derived under the assumption that the aspect ratio between wavelength and water depth is small. Since its derivation requires no assumption on wave amplitude, the model can be used to describe arbitrary amplitude waves. It is shown that the simple model captures the interesting features of strongly nonlinear solitary waves observed in previous numerical solutions. When compared with the case of zero vorticity, the solitary wave in uniform shear flows is wider when propagating upstream (opposite to the direction of surface drift), while it is narrower when propagating downstream. For the upstream-propagating solitary wave, a stationary recirculating eddy appears at the bottom when wave amplitude exceeds the critical value. For the case of downstream propagation, no eddy forms at the bottom but the solitary wave becomes more peaked, yielding a cusp at the critical wave amplitude, beyond which the solitary wave has a round wave profile. Although the appearance of the derivative singularity is inconsistent with the long-wave assumption in the model, round wave profiles away from the singularity are qualitatively similar to numerical solutions and observation.

Journal Article↗