Titanium dioxide (), which is one of the most basic materials in our daily life, plays a key role for environment purification. We synthesized nanoparticles by the hydrolysis reactions of titanium tetraisopropoxide using as a peptizing agent or as a chelating agent in the sol-gel method. The powder consisted of a rod shape or a spherical shape according to the concentration and kind of acid. The physical properties of nanoparticles were investigated with X-ray diffraction, SEM, BET analysis, and UV-Vis spectrophotometer.

The diapause duration P. ussuriensis eggs is known to either one year or prolonged to additional years. This complex life cycle is mainly caused by the interruption at two embryonic stages: early stage (initial diapause) and fully developed late stage (final diapause). The environmental cues, such as temperature, is critical to determine the diapause duration but the precise diapause mechanism of P. ussuriensis eggs is unclear. We demonstrated temperature effects on the entrance of initial diapause. Newly oviposited eggs were incubated at two temperature conditions (20℃and 30℃) for 60 days. When eggs were incubated at 20℃, egg weights were not significantly changed, but at 30℃ those were gradually increased to 1.5 times for 50 days. Genomic DNA contents of eggs were similarly increased at 30℃. Total RNA contents at 30℃ were highly increased from the 15-days-old but not at 20℃. In addition, we further analysed expression levels of two heat shock protein 70 (hsp70a, hap70b) genes during embryonic development. Our results suggest that initial diapause occurred between 10 and 15 days after oviposition and its entrance was blocked by high temperature incubation.

Spider mites are one of major pests in cultivations of various ornamental plants and also important in plant quarantine service. Due to the very small body size and high similarity within the Genus the identification of species is difficult even at the microscopic observation. To identify 5 major species (Tetranychus cinnabarinus, T. urticae, T. phaselus, T. kanzawai and T. truncatus) in the Genus Tetranychus at the molecular level, we designed 4 species-specific primer sets using nucleotide sequences of the internal transcribed spacer (ITS2) region in the nuclear ribosomal repeat unit. At the PCR diagnosis of extracted genomic DNAs of 5 species using each primer set, specific primers of both T. phaselus and T. truncates were species-specific to their own species samples. However, specific primer set of T. urticae detected T. cinnabarinus as well as T. urticae. Specific primer set of T. kanzawai detected T. truncates as well as T. kanzawai, even though detection intensities were lower in non-target species.

Due to the very small body size of spider mite, it is difficult to prepare DNA extraction simultaneously with slide samples from a single individual. Here we developed non-mashed DNA extraction method from a single spider mite to apply for molecular as well as morphological identification. Total genomic DNA was isolated from a single female adult using Genomic DNA extraction kit without the sample homogenization. DNA content of a single spider mite was 60-90 ng, which is sufficient for the PCR analysis. However, the quantity of extracted DNA and quality of the cuticle sample were dependent on the incubation time into the lysis buffer. Our results suggest that non-mashed DNA extraction method would be useful for the identification of very small mites as well as insects at the levels of DNA and morphology.

This study was conducted in order to investigate repeated-dose toxicities of Magnolia ovobata ethanol extract (MEE). MEE was administered orally to male and female Sprague Dawley rats at dose levels of 0, 500, 1,000, or 2,000 mg/kg for four weeks. Repeated administration of MEE did not induce abnormalities in general signs, body weight gain, feed and water consumption, necropsy findings, or organ weights. In addition, no abnormality was observed in hematological analyses; red blood cells and their indices, white blood cells, platelets, and coagulation times. In male rats, BUN and creatinine showed an increase at doses of 2,000 mg/kg and 500-1,000 mg/kg, respectively, while in female rats, lactate dehydrogenase and creatine phosphokinase showed a decrease at 2,000 mg/kg, the upper-limit dose of repeated-dose toxicity studies. However, there were no dose-dependent increases or gender-relationship. In addition, other parameters of the hepatic and muscular toxicities as well as energy and lipid metabolism were not affected. In microscopic examination, no considerable pathological findings were observed. The results indicate the safety of oral administration of MEE to the upper-limit dose.

The epidemiology of reported food-borne disease (FBD) outbreaks from 2001 to 2008 in Korea and Japan were compared in this study. The outbreak rate of FBD in Japan was significantly higher although the average number of patient in each outbreak in Korea was much higher. In both countries, summer was the season when most FBD outbreaks occurred. The comparison study revealed that FBD outbreaks in spring were more frequent in Korea, and outbreaks in winter were more frequent in Japan. Almost half of FBD outbreaks were observed at restaurants in both countries while FBD outbreaks at schools and work-places in Korea were much higher than in Japan. The most frequent cause of bacterial FBDs in Korea was pathogenic Escherichia coli followed by Salmonella species. On the other hand, Campylobacter jejuni was the most frequent source of bacterial FBDs in Japan. Norovirus, which is related to uncontrolled hand hygiene and involvement of ill food workers, was the main cause of viral FBDs in both countries. In conclusion, there are common epidemiological characteristics as well as several differences in FBD outbreaks of Korea and Japan. These are suggested to be originated from the characteristic of climate, food sources, and life styles in two countries. Establishment of stricter control and surveillance system for FBD outbreaks are required for prevention and reduction of FBD outbreaks in both countries.

This study analyzes a nationwide English placement test in the Rasch framework Data were obtained from 297 first-year junior high school students. The assessed person (.75) and item reliability (.95) indicate that the test was fairly consistent and reproducible with other samples of examinees. About 60% of total variation was explained under the assumption of unidimensionality. The person separation index suggests that two and a half ability levels can be differentiated by means of the test. Overall, the ability distribution of students was higher than the difficulty distribution of items. The fìt statistics identified a few misfìt items, but their impact on the utility of the test appears nonsignificant.

Insect pest monitoring program in subsistence warehouses can detect pest problems in early infestation stages. Temporal and spatial distributions of pests produced by monitoring allows facility managers and pest control operators to visualize pest problems and evaluate effectiveness of cleaning, sanitation and pest management practices. Pheromone-based insect monitoring traps were placed to study temporal and spatial distribution of Lepidopteran and Coleopteran stored product pests in two central distribution centers of United States Military Forces in the Republic of Korea, from March to December 2008. The two distribution centers receive store and issue subsistence and they are located in two different cities, Seoul and Taegu. As a result, three pests, Plodia inter punctella Hübner (Indian meal moth), Lasioderma serricorne F. (cigarette beetle), and Trogoderma variabile Ballion (warehouse beetle), were detected on the traps. P. interpunctella was most abundant, followed by L. serricorne and T. variabile. Different phenologies and spatial distribution of each species were seen from the two warehouses, that were related with internal temperature of the two warehouses and food availability. The program benefited to lead a better understandings for existence and extent of local pest problems in the two subsistence distribution centers, and also helped to find effective pest management periods and locations.

Developmental time, mummification, pupal mortality, sex ratio of a South Korean strain of Aphelinus varipes Förster parasitizing the green peach aphid, Myzus persicae were studied at 20, 25 and 30℃ in controlled climate cabinets. Plastic container with sweet pepper(Capsicum annuum L.) were used as experimental units. Green peach aphid in different larval instars and as adults, reared at the three different temperatures, were presented to A. varipes in a 'no-choice' and 'choice' situation for 6h. These presentations were done at 25℃ in each experiment to avoid an influence of temperature on parasitization rate. In case of no-choice test, more 1st(24%), 2nd(22%) and 3rd(38%) instar aphids were parasitized than 4th(14%) instar and adult(10%) among the aphids reared at 25℃. In case of choice test, more 1st(41%), 2nd(42%) and 3rd(29%) instar aphids were parasitized than 4th(13%) instar and adult(0%) among the aphids reared at 25℃. Pupal mortality of the parasitoid was not influenced by temperatures. The sex ratio of A. varipes was male-biased, and varied between 49.4% females developed from aphids reared at 30℃ and 42.8% from aphids reared at 20℃. The sex ratio was not significantly influenced by host stages. The developmental time of A. varipes parasitizing the green peach aphid ranged from 26.1days at 20℃ to 11.1days at 30℃.

Sexual dimorphism, the difference between sexes in secondary sexual characters, is in general driven by processes of sexual selection. The horn-headed cricket, Loxoblemmus doenitzi, exhibits sexual dimorphism in head shape, in which males have flat heads and triangular horns on both sides of their heads, whereas females have rounded heads and no horns. We hypothesized that male horns have been evolved due to intra-sexual selection in which males use these horns as weapons in aggressive interactions. To test this hypothesis, we conducted agonistic trials of field-caught males in L.doenitzi. Horn length was significantly correlated with thorax length and hind femur length. During agonistic males aggressively used their horns by beating the opponent’s horns with their horns or by poking the opponent’s body with their horns. However, the result of logistic regression analysis revealed that horn length or horn point frequency were not significant factors for contest outcome. Instead, body size was significant for determining contest outcome

Ten novel microsatellite loci were isolated and characterized from the soybean aphid, Aphis glycines. The soybean aphid was recently introduced into North America where it has become a serious pest of soybeans. This invasive pest has rapidly spread throughout the midwestern United States and southern Canada since 2000. The isolated loci were polymorphic, with two to 18 alleles in 20 individuals from a single population in Korea. The analyses revealed that 19 individuals had different multilocus genotypes, showing expected heterozygosity values ranging from 0.180 to 0.891. We report the development of microsatellite markers for A. glycines potentially suitable for further studies of population structure, dispersal, and host alternation.

Bacillus thuringiensis (Bt) is effective to control the diamondback moth, Plutella xylostella. However, its relative slow and unstable control efficacy limits its wide use by farmers. To facilitate pathogenic rate of Bt, a bacterial mixture technique has been developed in this study. Two entomopathogenic bacteria, Xenorhabdus nematophila (Xn) and Photorhabdus temperata temperata (Ptt), possess high immunosuppressive activity against several lepidopteran insects. The mixture treatments using Bt + Xn or Bt + Ptt significantly enhanced Bt pathogenicity in median lethal concentration and time. Though live Xn and Ptt bacterial cells gave significant effect on the pathogenicity, their 48 h culture broth after removing the bacterialcells still possessed the synergistic effect on the Bt pathogenicity. The larvae fed with the bacterial culture broth suffered significant immunosuppression in response bacterial to infection