OBJECTIVEThe number of people with metabolic syndrome is increasing worldwide, and changes in socioenvironmental factors contribute to this increase. Therefore, investigation of changes in metabolic syndrome and its components in South Korea, where rapid socioenvironmental changes have occurred in recent years, would be foundational in setting up an effective strategy for reducing this increasing trend.RESEARCH DESIGN AND METHODSWe compared the prevalence and pattern of metabolic syndrome among participants in the Korean National Health and Nutrition Examination Surveys for 1998, 2001, 2005, and 2007. In each survey, stratified, multistage, probability–sampling designs and weighting adjustments were conducted to represent the entire Korean population. The revised National Cholesterol Education Program criteria were used as the definition of metabolic syndrome. All biochemical parameters were measured in a central laboratory.RESULTSA total of 6,907 (mean ± SE age 45.0 ± 0.2 years), 4,536 (45.5 ± 0.2), 5,373 (47.1 ± 0.2), and 2,890 (49.9 ± 0.3) Koreans over 20 years of age have participated in the studies in 1998, 2001, 2005, and 2007, respectively. The age-adjusted prevalence of metabolic syndrome increased significantly from 24.9% in 1998, 29.2% in 2001, and 30.4% in 2005 to 31.3% in 2007. Among the five components, the level of low HDL cholesterol increased the most, by 13.8% over the 10 years. Abdominal obesity and hypertriglyceridemia followed, with 8.7 and 4.9% increases, respectively.CONCLUSIONSBecause dyslipidemia and abdominal obesity were major factors in increasing the prevalence of metabolic syndrome in Koreans for the past 10 years, lifestyle interventions should be conducted at the national level to reduce the burden and consequences of metabolic syndrome.

The association between 25-OHD inadequacy and subclinical atherosclerosis underscores the clinical implications of vitamin D status. An intervention strategy to increase vitamin D level through vitamin D-fortified diet and adequate sun exposure may mitigate the consequences of vitamin D deficiency.

A two-dimensional elastic-plastic finite element analysis is performed for plane stress conditions with 4-node isoparametric elements to examine closure behaviour of fatigue cracks, giving special attention to the determination of the most appropriate mesh sizes. It is found that a smaller mesh size does not always give more accurate simulation results in the fatigue crack closure analysis, unlike a conventional structural analysis. A unique, most-appropriate mesh size exists for a given loading condition that will provide numerical results which agree well with experimental data. The most appropriate mesh size can be determined approximately in terms of the theoretical reversed plastic zone sue. In particular, the ratio of the most appropriate mesh size to the theoretical reversed plastic zone size is nearly constant for a given stress ratio in the so-called crack-length-fixed method proposed in this study. By using the concept of the most appropriate mesh size, the finite element analysis can predict fatigue crack closure behaviour very well.Keywords-Fatigue crack closure; Finite element method; Most-appropriate mesh size, Crack-lengthfixed method. NOMENCLATURE a, a, = half crack length and initial crack length da/dN = crack growth rate E = Young's modulus H' = linear strain hardening parameter (du/ds) K , , , K-= maximum and minimum stress intensity factors due to applied loading KO, = opening stress intensity factor R = stress ratio (= K-IK,,) U = crack opening ratio [=(K,, -Kop)/(Kpu. -K-)] Aa, Aa* = mesh size and most appropriate mesh sue u,,,, u,, = opening and closing stress urnax, u-=maximum and minimum applied stress ur = yield stress v = Poisson's ratio up, Aup = theoretical monotonic and reversed plastic zone sizes

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Staphylococcus aureus is a major etiological pathogen for bovine mastitis, foodborne illness, and various clinical infections. Methicillin-resistant S. aureus (MRSA) has been isolated from bovine mastitic milk, and the presence of MRSA in milk is a major public health concern. We investigated the frequency of MRSA isolation from mastitic raw milk in Korea and characterized the patterns of antimicrobial resistance, virulence, and genotypes of the MRSA isolates. A total of 1,222 raw milk samples were collected from 47 dairy farms in Gyeonggi province from 2011 to 2012. Of these samples, 649 were considered mastitic milk based on somatic cell counts of more than 200,000 cells per ml, and 165 S. aureus isolates (from 25.4% of samples) were obtained from these samples. Of these isolates, 23 (13.9%) collected from five farms were confirmed as MRSA by detection of the mecA gene. Disk diffusion and MIC tests for antibiotic resistance revealed that all MRSA isolates were resistant to four or more antimicrobial agents. All MRSA isolates had staphylococcal enterotoxin genes, and two clusters of these genes were identified: seg-sei-sek-sem-sen-seo (20 isolates, 87%) and sed-seg-sei-sej-sem-sen-seo (3 isolates, 13%). Each MRSA-positive farm had only one spa-SCCmec type. Nine MRSA isolates (39.1%) with the t324-IVa genotype, which is related to community-acquired MRSA infection, were isolated from three dairy farms. Additional genotypes of t148-IVa and t002-II were detected and related to human MRSA strains. Most MRSA isolates had distinct pulsed-field gel electrophoresis subtypes, indicating they were not the same clones. Only two isolates collected from the same farm during different years had an identical electrophoresis type, indicating persistence of the clone at this farm. Taken together, these findings may indicate an increased virulence and risk of MRSA strains on dairy farms. Therefore, an efficient surveillance and control program is needed to prevent the transmission of MRSA from animals to humans.

Behaviour of fatigue crack growth and closure through a compressive residual stress field is investigated by performing fatigue crack growth tests on welded SEN specimens of a structural steel (JIS SMSOA). Depending on the type of the initial residual stress in the region of crack growth, the growth and closure of the crack show different behaviour. In particular, in the transition region from a compressive residual stress field to a tensile residual stress field, the fatigue crack growth rates cannot be described by the effective stress intensity factor range AKeR, based on the measured crack opening stress intensity factor 4,. Also it is found that the R-method using the data of da/dN vs AK for residual stress-free specimens, with the effective stress ratio R'[ = (K,,,,, + Kr)/(Kmin + &)I, gives non-conservative predictions of the growth rates in the transition region. Observations of crack closure behaviour in this study indicates that partial opening of the crack occurs and this plays an important role in crack growth through a compressive residual stress field. Based on the concept of a partial opening point (defined and measured in this work), fatigue crack growth behaviour can be better explained.

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