Predictors of Sexual Behavior among Korean College Student: Testing the Theory of Planned Behavior

Purpose: This study examined the relationships among variables derived from Ajzen's Theory of Planned Behavior (TpB) in order to explain intentions of premarital sex and condom use in Korean college students. Methods: This study used a cross-sectional, correlational design using an exploratory survey methodology through self-reported questionnaires. Several instruments were used to measure the variables studied. Students aged 18-25 were recruited from a university in Seoul, Korea using a flyer and self-referral (male =165, mean age: 22.6; female=133, mean age: 20.67). Since there was a small amount of missing data (6.88%) and no differences in sample characteristics between the missing (n=22) and the non-missing groups (n=298), list-wise deletion was performed. The analytic approach included descriptive statistics, spearman rank correlation, and multi-sample structure equation modeling. All instruments showed good reliabilities. Cronbach's alphas were used to examine internal consistencies of the instruments (alpha=0.77 - 0.98). Results: Forty nine percent of male students and around 12% of the female students had engaged in premarital sex; however, only 26.7% of sexually active students always used condoms. Looking at the model of premarital sex, premarital attitude was the strongest predictor of intention of premarital sex for both genders. For males, the TpB components of attitude, perceived behavior control, subjective norms explained intention of premarital sex; however, perceived behavioral control did not predict intention of premarital sex for females. A Lagrange Multiplier (LM) test showed that male and female students had different models to explain intention of premarital sex (S-B chi-square test(22) =20.55, p=0.55, CFI=1.00, RMSEA=0.000). Looking at the model of condom use, condom efficacy was the strongest predictor of intention of condom use, and all TpB components significantly predicted intention of condom use. Higher condom efficacy predicted a higher intention. The LM test showed that male and female students shared one model to explain this intention (S-B chi-square test(17) =22.72, p=0.16, CFI=0.98, RMSEA=0.03). Conclusion: The TpB has demonstrated applicability for predicting intentions of premarital sex and condom use as a way to decrease risky sexual behavior within the Korean culture. Findings provide information for developing better sex education programs for Korean late adolescents and young adults

Optimization of isoprene production using a metabolically engineered Escherichia Coli

The volatile C5 hydrocarbon, isoprene is an important platform chemical, which has been used in the manufacture of synthetic rubber for tires and also has the potential for various other applications such as elastomers and adhesives. Moreover, isoprene is convertible to biofuel blend stocks such as C10 gasoline, C15 diesel, and jet fuels because of its higher energy content than other biofuels. Although isoprene is currently derived from petroleum, its sustainable supply has been suffered from price fluctuation of crude oil, high refining cost and energy consumption, and low recovery yield of pure isoprene. As an alternative, the biologically produced isoprene (bio-isoprene) has been developed rapidly for the last decade. Bio-isoprene is synthesized from dimethylallyl diphosphate (DMAPP), which is derived from mevalonate (MVA) pathway or the methylerythritol phosphate (MEP) pathway, by isoprene synthase. In this study, metabolic engineering for enhanced production of bio-isoprene was performed by deletion of relevant genes and optimization of culture condition. In comparison of isoprene production between E.coli DH5α and MG1655, lower isoprene production was observed in MG1655. The lower isoprene production in E. coli MG1655 was ascribed to the presence of recA gene which is absent in the DH5α strain. The deletion of recA gene in E.coli MG1655 allows higher isoprene production than E. coli DH5α. Moreover, the optimized expression of isoprene synthesis pathway with 0.03mM IPTG induction enhanced the isoprene production up to 2,850 mg/L. Overall, isoprene production through the optimization was improved by 28.5-fold compared to the initial production of MG1655 strain. Please click Additional Files below to see the full abstract

Reliability Evaluation considering Structures of a Large Scale Wind Farm

Wind energy is one of the most widely used renewable energy resources. Wind power has been connected to the grid as large scale wind farm which is made up of dozens of wind turbines, and the scale of wind farm is more increased recently. Due to intermittent and variable wind source, reliability evaluation on wind farm is necessarily required. Also, because large scale offshore wind farm has a long repair time and a high repair cost as well as a high investment cost, it is essential to take into account the economic aspect. One of methods to efficiently build and to operate wind farm is to construct wind farm which is able to enhance a capability of delivering a power instead of controlling an uncontrollable output of wind power. Therefore, this paper introduces a method to evaluate the reliability depending upon structures of wind farm and to reflect the result to the planning stage of wind farm

A systematic mRNA control mechanism for germline stem cell homeostasis and cell fate specification

Germline stem cells (GSCs) are the best understood adult stem cell types in the nematode Caenorhabditis elegans, and have provided an important model system for studying stem cells and their cell fate in vivo, in mammals. In this review, we propose a mechanism that controls GSCs and their cell fate through selective activation, repression and mobilization of the specific mRNAs. This mechanism is acutely controlled by known signal transduction pathways (e.g., Notch signaling and Ras-ERK MAPK signaling pathways) and P granule (analogous to mammalian germ granule)-associated mRNA regulators (FBF-1, FBF-2, GLD-1, GLD-2, GLD-3, RNP-8 and IFE-1). Importantly, all regulators are highly conserved in many multi-cellular animals. Therefore, GSCs from a simple animal may provide broad insight into vertebrate stem cells (e.g., hematopoietic stem cells) and their cell fate specification. [BMB Reports 2016; 49(2): 93-98

Probabilistic prediction of cyanobacteria abundance in a Korean reservoir using a Bayesian Poisson model

There have been increasing reports of harmful algal blooms (HABs) worldwide. However, the factors that influence cyanobacteria dominance and HAB formation can be site‐specific and idiosyncratic, making prediction challenging. The drivers of cyanobacteria blooms in Lake Paldang, South Korea, the summer climate of which is strongly affected by the East Asian monsoon, may differ from those in well‐studied North American lakes. Using the observational data sampled during the growing season in 2007–2011, a Bayesian hurdle Poisson model was developed to predict cyanobacteria abundance in the lake. The model allowed cyanobacteria absence (zero count) and nonzero cyanobacteria counts to be modeled as functions of different environmental factors. The model predictions demonstrated that the principal factor that determines the success of cyanobacteria was temperature. Combined with high temperature, increased residence time indicated by low outflow rates appeared to increase the probability of cyanobacteria occurrence. A stable water column, represented by low suspended solids, and high temperature were the requirements for high abundance of cyanobacteria. Our model results had management implications; the model can be used to forecast cyanobacteria watch or alert levels probabilistically and develop mitigation strategies of cyanobacteria blooms. Key Points A Bayesian hurdle Poisson model predicted cyanobacteria abundance Temperature, flushing rate, and water column stability were key factors The model forecasted cyanobacteria watch and alert levels probabilisticallyPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106958/1/wrcr20820.pd