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        검색결과 74

        1.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Maca has been reported to alleviate male menopause symptoms in humans and experimental animals; however, its mechanism of action in improving male menopause has not been clearly identified. This study aimed to investigate the mechanism of action of gelatinized maca in improving male menopause by analyzing serum testosterone, testicular androgen receptor (AR) expression, and testicular oxidation-antioxidation balance. Gelatinized maca was administered orally to aged male C57BL/6 mice at three doses (500, 1,000, and 1,500 mg/kg/day) for 28 consecutive days. Serum biochemical analysis showed an increase in serum hydroxysteroid 17-beta-dehydrogenase 13 (HSD17β13) concentration at 1,500 mg/kg/day and a decrease in serum sex hormone-binding globulin (SHBG) concentration at ≥ 1,000 mg/kg/day. Gelatinized maca administration also resulted in the increased expression levels of testicular AR and cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) at 1,500 mg/kg/day. Oxidative stress analysis showed an increase in testicular superoxide dismutase and glutathione reductase activities and a decrease in testicular malondialdehyde at 1,500 mg/kg/day. In conclusion, gelatinized maca administration to aged male mice increased HSD17β13, AR and CREB expression, and antioxidant capacity and decreased serum SHBG. The results of the present study suggest that gelatinized maca may be a useful substance that can help alleviate male menopause symptoms.
        4,000원
        2.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The development of thermoelectric (TE) materials to replace Bi2Te3 alloys is emerging as a hot issue with the potential for wider practical applications. In particular, layered Zintl-phase materials, which can appropriately control carrier and phonon transport behaviors, are being considered as promising candidates. However, limited data have been reported on the thermoelectric properties of metal-Sb materials that can be transformed into layered materials through the insertion of cations. In this study, we synthesized FeSb and MnSb, which are used as base materials for advanced thermoelectric materials. They were confirmed as single-phase materials by analyzing X-ray diffraction patterns. Based on electrical conductivity, the Seebeck coefficient, and thermal conductivity of both materials characterized as a function of temperature, the zT values of MnSb and FeSb were calculated to be 0.00119 and 0.00026, respectively. These properties provide a fundamental data for developing layered Zintl-phase materials with alkali/alkaline earth metal insertions.
        4,000원
        7.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The optimal determination of seeding rate is critical to minimizing uncertainties about the large variations observed in forage quality and productivity when alfalfa is cultivated under different geographical areas and growing conditions. The objective of this investigation was to provide information about the proper seeding rate according to harvest timing for alfalfa cultivation in the Northern regions of Korea. Alfalfa was sown in September 2018 at a seeding rate of 20, 30 or 40 kg/ha and harvested four times in 2019: May 3, July 2, September 11, and October 13. Regardless of seeding rate, alfalfa plant height was longest at the third harvest (113 cm) and the shortest in the last annual harvest (43.8 cm). However, seeding rate had no effect on alfalfa plant height at any harvest. Forage relative feed value was increased in the first cutting but decreased in the third cuttings as seeding rate increased. However, seeding rate had slight effect on alfalfa forage quality components at the second and fourth cuttings. Total annual DM and crude protein production (in 4 harvests) was greater at higher seeding rates. Plots seeded at a rate of 40 kg/ha produced on average 1,257 and 2,620 kg/ha more forage (DM basis) than those seeded at a rate of 30 or 20 kg/ha, respectively. Forage DM production at the first, second, third, and fourth harvests accounted for 36.1, 24.0, 27.1, and 12.8 % of total annual DM production, respectively. Overall, small differences were seen when alfalfa seeding rate was different but maximum forage DM production (in four harvests) was detected when seeding rate was 40 kg/ha. These data could be useful to the alfalfa growers by allowing them to make more accurate trade-offs between seed price and the expected magnitude of forage yield gains in order to select the best seeding rate.
        4,000원
        8.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cutting management has been identified as a critical factor in the alfalfa production systems because it has a significant impact on maximizing yield and maintaining the forage quality. The objective of this experiment was to determine the proper cutting height according to harvesting time for optimizing nutrient yield and forage nutritive quality of alfalfa grown in alpine regions of Korea. Alfalfa was sown at a seeding rate of 30 kg/ha in August 2018 and harvested at four cuttings in 2019 (3 May, 2 July, 11 September, and 13 October). Cutting heights were adjusted at 5, 15, and 25 cm above the soil surface. Alfalfa plant was tallest at the third cutting (109 cm), which was on average 35 cm taller than the first or second cutting. Relative feed value (RFV) remained unaffected by cutting height at the first harvest, but increased consistently in subsequent harvests as cutting height increased. Alfalfa collected at the first and fourth cuttings had the highest RFV (mean 152), which was on average 8 and 67 units higher than the second and third harvests, respectively. At each harvest, in vitro dry matter digestibility was highest in alfalfa cut at a 25-cm height. Dry matter (DM) production at each cutting height was highest in the first cutting, accounting for on average 36-37% of total annual DM production, and lowest in the fourth harvest, accounting for about 11-13% of the total DM yield. The total dry matter production (in four harvests) was 4,218 kg/ha higher when alfalfa was subjected to a cutting height of 5 cm rather than 25 cm. Cutting height had no effect on total crude protein yield, but from the first to fourth cutting, the protein yield followed a decreasing trend. Finally, there were visible declines in forage nutritive quality when alfalfa was cut at a shorter height. However, the magnitude of difference in total forage yield may outweigh the slight decline in forage quality when alfalfa is cut at a lower height. The findings of this study could help the alfalfa growers make better harvest management decisions.
        4,000원
        11.
        2019.04 구독 인증기관·개인회원 무료
        최근 다양한 유기재배 작물의 뿌리를 가해하는 굼벵이류의 피해가 증가하고 있으나, 굼벵이류는 토양 내 발생하는 특징으로 인해 발생시기 및 그 종류에 대한 확인이 어려운 해충이다. 피해를 끼치는 굼벵이의 발생을 파악하기 위해 고구마 유기재배지에 페로몬 트랩을 이용하여 굼벵이의 성충의 종류 및 발생 동향을 조사하였다. 조사지는 무안 유기재배농가와 국립농업과학원 완주군 포장에서 이루어졌다. 3종의 풍뎅이 페로몬 루어를 유인제로 사용하였으 며 6월 초부터 8월 말까지 조사지에 트랩을 설치하여 포획된 풍뎅이를 수집하여 동정을 하였다. 유기재배포장에서 포획된 종은 큰검정풍뎅이, 콩풍뎅이, 청동풍뎅이, 녹색콩풍뎅이, 별줄풍뎅이 등의 풍뎅이와 흰점박이꽃무지 등이 주로 채집되었다. 유기재배 고구마포장에서 풍뎅이 발생소장을 조사한 결과 최대로 발생한 시기는 7월초였다.
        12.
        2019.04 구독 인증기관·개인회원 무료
        Japanese pine sawyer, Monochamus alternatus, is the main pest that mediates pine wilt nematode, Bursaphelenchus xylophilus, that causes serious damage to pine forests. In this study, we studied the strategy to control M. alternatus using entomopathogenic fungi. The fungi were collected from soil by an insect-baiting method and two fungal isolates (Metarhizium anisopliae JEF-197 and JEF-279) showed high virulence against M. alternatus. The Metarhizium isolates were evaluated for insecticidal activity against M. alternatus by spray treatment on live pine trees and wintering trees, and the M. anisopliae JEF-197 showed high insecticidal activity. In addition, the interaction of fungi and M. alternatus were analyzed by RNA-seq. This result can contribute to the development of insect control agents using entomopathogenic fungi.
        13.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Interferon-tau (IFNT) is known as a major conceptus protein that signals the process of maternal recognition of pregnancy in ruminants. Also, multiple interferon genes exist in cattle, However, molecular mechanisms of these bovine IFNT (bIFNT) genes whose expressions are limited have not been characterized. We and others have observed that expression levels of bovine subtype IFNT genes in the tissues of ruminants; thus, bIFNT1 and other new type I (bIFNTc1/c2/c3) gene co-exist during the early stages of conceptus development and non-trophoblast cells. Its genes transcription could be regulated through CDX2 and ETS2 and JUN and/or cAMP-response element binding protein (CREB)-binding protein (CREBBP) expression, a transcription factor implicated in the control of cell differentiation in the trophectoderm. Bovine ear-derived fibroblast cells, were co-transfected with luciferase reporter constructs carrying upstream (positions -1000 to +51) regions of bIFNT1 and other new type I gene and various transcription factor expression plasmids. Compared to each - 1kb-bIFNT1/ c1/c2/c3-Luc increased when this constructs were co-transfected with CDX2, ETS2, JUN and/or CREBBP. Also, Its genes was had very effect on activity by CDX2, either alone or with the other transcription factors, markedly increased luciferase activity. However, the degree of transcriptional activation of the bIFNTc1 gene was not similar to that bIFNT1/c2/c3 gene by expression plasmid. Furthermore, Sequence analyses also revealed that the expression levels of bIFNT1/c2/c3 gene mRNAs expression were highest on day 17, 20 and 22 trophoblast and, Madin-Darby bovine kidney (MDBK), Bovine ear-derived fibroblast (EF), and endometrium (Endo) non-trophoblast cells. But, bIFNTc1 mRNA had not same expression level, bIFNTc1 lowest levels than those of IFNT1/c2/c3 gene in both trophoblast and non-trophoblast cells. These results demonstrate that bovine subtype bIFNT genes display differential, in the trophoblast and non-trophoblast cells.
        4,000원
        14.
        2018.11 구독 인증기관·개인회원 무료
        Variance of conceptus interferon tau (IFNT), produced by the embryonic trophectoderm, is known as a major conceptus protein that signals the process of maternal recognition of pregnancy in ruminants, essential for the maintenance of early pregnancy. Similar to other IFN genes such as IFNA and IFNB, multiple IFNT genes are present. However, some kinds of IFNT genes actively transcribed and regulated in bovine conceptuses have not been well characterized. In this study, during the course of bovine IFNT gene transcription through the use of next generation sequencer SOLiD3, revealed that among 38 IFN genes registered, only two transcripts, IFNT1 and IFNTc1, were found in conceptuses during early pregnancy. Also, to identify a transcription factor(s) involved in the regulation of IFNT genes, mRNAs for various known transcription factors were investigated by real-time PCR in conceptus tissues, respectively. Furthermore, compared to the IFNT genes, IFNT1 and IFNTc1 had same active levels, which were previously shown to correlate with the appearance of effective antiviral activity. However, the expression levels of these Luc activities differed. Bovine ear fibroblast (EF) cells were cotransfected with luciferase reporter constructs carrying upstream (–631 to -51) promoter regions of IFNT1 or IFNTc1 and various transcription factor expression plasmids, CDX2, AP1(JUN), ETS2 and/or cAMP-response element binding protein (CREB)-binding protein (CREBBP). CDX2, either alone with the other 2 transcription factors, was found to increase luciferase activity approximately 14- and 11-folds, respectively. The degree of transcriptional activation of the IFNTc1 gene was not similar to that IFNT1 gene by AP1, ETS2 or/and CREBBP, expression plasmid. These results suggest that two isoforms of bovine conceptus IFNT genes are regulated differently in conceptuses during early pregnancy.
        15.
        2018.10 구독 인증기관·개인회원 무료
        To control an external parasitic mite, a honey bee line possessing high hygienic behavior (HHB) against an external parasitic mite, Varroa destructor, has been bred in South Korea and an assessment method has been necessitated to diagnose HHB line from the low hygienic behavior (LHB) line. Thus, in this study, we developed single nucleotide polymorphism (SNP) markers from whole genome sequencing of each 20 worker bees from HHB and LHB lines of A. mellifera ligustica (Hymenoptera: Apidae). An average of 319,445,977 sequence reads was mapped to the known A. mellifera reference genome (an average of 87.46%). In 2,316,128 and 3,266,756 SNPs from each HHB and LHB line, an average of 93.6% and was located in the intergenic spacers and introns, whereas, the remaining 6.4% was located in the genic region, respectively. Among them 20 SNPs that were fixed at each line possessing within-individual homozygosity were selected and each four SNPs were used to diagnose the two honey bee lines either by typical PCR-restriction fragment length polymorphism method or allele-specific PCR. The remaining six SNPs had the size difference, enabling relatively easy differentiation between the two honey bee lines on typical agarose gel and another remaining six SNPs only has sequence difference including SNP sites. Thus, these SNP markers can be used to diagnose the honey bee line with HHB from LHB line against V. destructor.
        16.
        2018.10 구독 인증기관·개인회원 무료
        Japanese pine sawyer beetle, Monochamus alternatus Hope (Coleoptera: Cerambycidae) is considered as a serious pest in pine trees. To develop an eco-friendly strategy to manage this forest insect, we collected entomopathogenic fungi from Korean soil and assessed their virulence against the adults of the insect in laboratory conditions. As a result, two isolates with conidial suspension (1.0×107conidia/ml), showed 87% and 90% mortality 12 days after fungal treatment, respectively. We assessed the potential of the fungi-derived destruxin and protease as additives to the fungal isolates, and they showed insecticidal activity via feeding and spraying treatments. Finally, we produced fungal conidia in massive solid cultures and formulated wettable powders, and now studying optimal conditions of oil-based formulation with two isolates. Based on these results, we are evaluating the control efficacy of the fungal agents against M. alternatus in field conditions.
        17.
        2018.05 구독 인증기관·개인회원 무료
        Pavement performance usually depends on the pavement’s material property, traffic and environmental conditions. Current pavement design programs such as the Mechanistic Empirical Pavement Design Guide use these factors in assessing the pavement life and performance in terms of different distresses like rutting and fatigue cracking. Theoretically, the cracking and rutting behaviour of pavements are based on accumulated strains experienced by the pavement which is brought by the weight and loading speed of vehicles. A steady state loading device was used in the field to evaluate pavement deflection’s behaviour in varying loading frequencies. It was observed that the pavement deflection increases as the loading frequency also increases until it approaches a certain frequency wherein the deflection decreases thereafter. In this study, a three-dimensional finite element pavement model was established using ABAQUS wherein the effect of the vehicle’s loading frequencies was analysed. The calculated static deflection and stress from the finite element (FE) model were found to have good correlation with the KENPAVE measured deflection and stress. The deflections of different pavement conditions were further studied and analysed by generating several pavement geometries and strength from the FE model using a frequency sweep response analysis. It was found that the geometric condition and the current modulus of the pavement can amplify the pavement deflection by a factor, β, depending on the loading frequency. The peak deflection was found to be occurring when the loading frequency approaches one of the pavement’s natural frequencies. Based on the finding from this study, the natural frequency is an important factor to be considered in designing pavements. Further study is recommended to understand more on how to minimize the effect of natural frequency to pavement life.
        18.
        2018.04 구독 인증기관·개인회원 무료
        Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae) in forest is considered as a serious forest pest in pine trees. In this study, we collected entomopathogenic fungi from soil and assessed their virulence against the adults of the inset using a spray method in laboratory condition. Two entomopathogeinc fungi isolates showed high virulence against the adults. In the concentration of 1.0 × 107conidia/ml, the mortality rate of the adults were 53% and 60%. In semi-field condition, one isolate showed a virulence of 60% against the adult. Consequently, we confirmed the possibility of the fungal isolates in controlling the beetles. In near the future, we will investigate several factors which is possibly related to the control of the forest insect pest using entomopathogenic fungi in field conditions, given the importance of fungal formulation and practical application methods.
        19.
        2017.10 구독 인증기관·개인회원 무료
        Chemical pesticides have been used for persimmon pest control, however the overuse caused insect resistance andenvironmental toxicity. Herein this work, we investigated the biological potential of eco-friendly organic pesticides (biologicals)and entomopathogenic fungi in controlling persimmon pests, Stathmopoda masinisaa and Riptortus pedetris. A botanicalmixture of Chinese scholar tree, goosefoot and subtripinnata extract, Bacillus thuringesis NT0423 and one isolate of Beauveriabassiana showed high insecticidal activity against the pests in laboratory conditions. The selected botanical extract andmicroorganism were combined with a chemical pesticide (buprofezin+dinotefuran WP) and were assessed their controlefficacy in persimmon fields. Compared to the three times of chemical spray, the combination of more than one timeof chemical spray and the selected biologicals controlled the persimmon pests with an acceptable levels. Consequentlyone time of biological spray can be integrated to the spray program where only chemicals are strongly considered.
        20.
        2017.10 구독 인증기관·개인회원 무료
        This study was carried out to investigate insect community structure from different habitats in Baengnyeong island.We performed day and night collection at two different habitats (mountain, rural area) of Baengnyeong island from Mayto September in 2015. A total of 2,879 individuals of 404 species, 81 families belonging to 10 orders were collectedand identified. A dominant species was Idisia ornata Pascoe (Tenebrionidae) despite a very low percentage (6.04%) ofthe species among the catches. Results of independent t-test showed a significant high (p<0.001) of species richness onmountain. Also, seasonal results of ANOVA (Analysis of variance) were significantly influential with species abundanceand species richness. The result of NMDS analysis showed that the community structure of the insects from the mountainis different with rural area.
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