• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.67-74
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• 2013

This research was conducted to investigate the competition for survival between the two cricket species: Gryllus bimaculatus (GB) and Teleogryllus emma (TE). The test insects for this research were bred in the greenhouse of the Ecological Entomology Lab, College of Agriculture and Biosciences, Kyungpook National University, Korea. The feeding environment was $28^{\circ}C$ to $30^{\circ}C$, Long-Day condition (16L : 8D) and Relative Humidity: 50%~60%. The changes of the individual number in two species (TE, GB) were checked every day. This research had three experimental conditions which the ratios of individuals (TE : GB) were set at 1 : 2, 1 : 1 and 2 : 1. The survival rate of GB was net better than that of TE in the result of this study. However, due to the absence of the diapauses period in the egg stage, GB would dominate over TE in the field condition. The appropriate legal measure against GB is recommended.

• Journal of Life Science
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• v.32 no.3
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• pp.196-201
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• 2022

Insects have been proposed as new protein sources for human nutrition, and protein availability is affected by insect characteristics. Fermentation can be used to obtain a variety of insect-based ingredients and products with unique properties, but its effect on protein availability is unknown. Fermented cricket (Gryllus bimaculatus) powder consists mainly of protein, and its oral administration has been reported to improve hair growth in androgenetic alopecia. The purpose of this study was to evaluate the hair-promoting activity of fermented cricket powder in an animal model using male C57BL/6 mice (25-30 g). The abdominal hair of the mouse (2x2.5 cm) was gently removed, and the groups fed as follows: Intact controls (no cricket powder); cricket powder only; and fermented cricket powder only. Food was applied daily for 11 weeks. Observational and physical examinations were performed and the results of the different groups compared. The application of fermented cricket powder significantly (p<0.01) promoted hair growth compared to the intact controls. The C57BL/6 results confirmed increased growth after seven weeks when the proportion of anagen follicles had increased by about 125% and 120% in the control and cricket powder groups, respectively. In conclusion, fermented cricket powder can be seen as a promising alternative alopecia treatment because it promotes hair growth, and, given the powder's composition, trace elements such as amino acids may have contributed to these effects.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.309-316
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• 2017

In baseball, estimation of winning percentage is critical and many studies for this topic have been actively performed. Pairwise winning percentage estimation using Pythagorean winning percentages of individual teams against other individual teams has the property that the sum of estimated winning percentage totals must be a constant. In this paper, we consider two types of pairwise estimation including linear formula and Pythagorean formula to the Korean baseball data of seasons from 2013 to 2016 under the criterions of RMSE and MAD. In conclusion, pairwise Pythagorean methods have the smaller RMSE and MAD than traditional Pythagorean methods. We suggest the optimal pairwise Pythagorean formula with a fixed exponent. Also we show that there are very little differences of RMSE and MAD between variation in exponent values.

• The Korean Journal of Applied Statistics
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• v.33 no.4
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• pp.439-449
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• 2020

Meta-analysis provides a way of integrating several independent studies of interest. Since small studies with statistically significant results are more likely to be published, publication bias, which is a special case of selection bias, often occurs in meta analysis. Conditional likelihood and weighted estimating equation have been proposed to deal with publication bias, but they require to specify a correct selection probability model. In contrast, the pairwise pseudolikelihood approach can correct publication bias without fully specifying the correct selection probability model, but its performance in meta-analysis was not investigated. In this paper, we perform a numerical study about whether the pairwise pseudolikelihood approach is effective for solving publication bias arising from typical meta-analysis settings.

• Korean Journal of Food Science and Technology
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• v.51 no.5
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• pp.480-485
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• 2019

The present study was conducted to compare antioxidant capacities of protein hydrolysates from four different edible insects (Protaetia brevitarsis larvae, Allomyrina dichotoma larvae, Gryllus bimaculatus imago, and Tenebrio molitor larvae) which have recently been registered as food varieties in Korea. Protein hydrolysates were prepared from each insect using enzymatic hydrolysis using alcalase, and were then separated into a fraction containing ${\leq}3kDa$. According to $RC_{50}$ values and trolox equivalent antioxidant capacity results obtained from five different antioxidant analyses, the Gryllus bimaculatus (GB) hydrolysate showed relatively high levels of antioxidant capacity and, in particular, the GB hydrolysate showed considerably strong antioxidant activities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and in ferric reducing antioxidant power (FRAP) assays. The GB hydrolysate also showed the strongest inhibitory effect on peroxidation of linoleic acid, and its rate of inhibition at $100{\mu}g/mL$ on day 3 of treatment was 60.26%. These results suggest that protein hydrolysates from edible insects including GB represent potential sources of natural antioxidants.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.236-243
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• 2023

Platelets act a fundamental role in primary- and secondary-hemostasis, however, platelet activation may cause thrombosis simultaneously. Therefore, control of platelet aggregation is crucial in preventing thrombosis-mediated diseases. Recently, the development of insect materials is attracting attention. Among the highly nutritious functional food sources, insects such as two-spotted cricket (Gryllus bimaculatus). Gryllus bimaculatus (G. bimaculatus) contains high protein and unsaturated fatty acids and has been registered as a food material September 2015 by the Ministry of Food and Drug Safety of Korea. In this study, we examined whether G. bimaculatus extract (GBE) inhibits platelet aggregation, intracellular calcium mobilization, thromboxane A₂ production and glycoprotein IIb/IIIa (integrin αIIb/β3) activation. We investigated whether GBE can regulate signaling molecules, such as 1, 4, 5-triphosphate receptor type I, extracellular signal-regulated kinase, cytosolic phospholipase A₂, mitogen-activated protein kinases p38, vasodilator-stimulated phosphoprotein, phosphatidylinositol-3 kinase, Akt, glycogen synthase kinase-3α/β, and SYK. Taken together, GBE is a potential therapeutic drug candidate to prevent platelet-related thrombosis and cardiovascular disease.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.1013-1024
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• 2015

We compare the performance of two representative estimation methods for the dynamic conditional correlation (DCC) GARCH model. The first method is the pairwise estimation which exploits partial information from the paired series, irrespective to the time series dimension. The second is the multi-dimensional estimation that uses full information of the time series. As a simulation for the comparison, we generate a multivariate time series similar to those observed in real markets and construct a DCC GARCH model. As an empirical example, we constitute various portfolios using real KOSPI 200 sector indices and estimate volatility and VaR of the portfolios. Through the estimated dynamic correlations from the simulation and the estimated volatility and value at risk (VaR) of the portfolios, we evaluate the performance of the estimations. We observe that the multi-dimensional estimation tends to be superior to pairwise estimation; in addition, relatively-uncorrelated series can improve the performance of the multi-dimensional estimation.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.78-81
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• 2015

This study aimed to determine a feed withdrawal duration time of Gryllus bimaculatus (Gb), for removal of intestinal feces. Finally, this species of cricket has been temporarily approved for use as a human food source in Korea. To commercialize Gb as an edible insect, we attempted to prevent the proliferation of micro-organisms and improve taste of Gb by removing intestinal feces of live crickets. Our study showed that weak crickets were damaged in 2 days after feed withdrawal in farm. The microscope findings also revealed that feces of strong crickets' intestine almost disappeared at 1 day after feed withdrawal and instead, some of arms and legs of weak crickets were observed in the former's intestine. The results suggest that 1 day is deemed to be an adequate time for feed withdrawal, when it usually takes 1 day to deliver live crickets from the farm to a destination.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.171-178
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• 2022

In this study, the quality characteristics of rice cookies supplemented with different types of insect powder (Tenebrio molitor, Protaetia brevitarsis, and Gryllus bimaculatus) were assessed according to the quantity of insect powder used (0, 1, 2.5, 5, and 7.5 g). No significant differences were observed in rice cookie densities or water content. The pH value and spread factor decreased with increasing insect powder content (p<0.05); however, a significant increase was observed in the loss rate (p<0.05). Crude ash, crude fat, and crude protein content significantly increased with higher concentrations of insect powder (p<0.05). Moreover, lightness and yellowness decreased, whereas redness increased with higher insect powder concentrations (p<0.05). Hardness significantly decreased, whereas the antioxidant capacities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals increased with higher insect powder concentrations (p<0.05). Finally, insect powder can prove a valuable resource in rice cookie production, considering its nutritional value, consumer preference, and antioxidant properties.

• The Journal of Natural Sciences
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• v.11 no.1
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• pp.15-17
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• 1999

Let {f(n)} be an increasing sequence such that f(n)>0 for each n and f(n)$\rightarrow$$\infty$. Let {X$_n$,n$\geq1$} be a sequence of pairwise independent random variables. In this paper we give sufficient conditions on {X$_n$,n$\geq1$} such that $sum_{i=1}^n$(X$_i$-EX$_i$)/f(n) converges to zero almost surely.