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        검색결과 39

        1.
        2022.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Interest in the use of semiconductor-based photocatalyst materials for the degradation of organic pollutants in a liquid phase has grown, due to their excellent performance and response to the light source. Herein, we fabricated a NiO-SiCTiO2 ternary structured photocatalyst which had reduced bandgap energy, with strong activation under UV-light irradiation. The synthesized samples were examined using XRD, SEM, EDX, TEM, DRS, EIS techniques and photocurrent measurement. The results confirmed that the two types of metal oxides were well bonded to the SiC fiber surface. The junction of the new photocatalyst exhibited a large number of photoexcited electrons and holes. The holes tended to oxidize the water and form a hydroxyl radical, which promoted the decomposition of methylene blue. The close contact between the 2D SiC fiber and metal oxide semiconductors expanded the scope of absorption wavelength, and enhanced the usability of the ternary photocatalyst for the degradation of methylene blue. Among three synthesized samples, the NiO-SiC-TiO2 showed the best photocatalytic effect, and was considered to have excellent photoelectron transfer due to the synergy effect between the metal oxide and SiC.
        4,000원
        3.
        2020.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Cancer is the second leading cause of death worldwide and currently there are many approaches developing towards cancer treatment. Cancer treatments like chemotherapy and radiation therapy are often painful and have adverse effects. The mechanism of apoptosis is a complex process and it involves different pathways in its mechanism of action. Apoptosis can be caused by signals within the cell such as stress, or by extrinsic signals such as ligands binding to cell surface death receptors. The programmed cell death plays a important role in the several physiological and pathological processes. It plays important role in homeostasis. Flavonoids have gained importance as anticancer agents promoting cytotoxicity and apoptosis in cancer cells. Flavonoids are present in many medicinal plants which are a kind of ubiquitous natural products and essential active ingredients. They have strong biological activities with high efficiency and low toxicity, possessing good preventive and cure effects on different tumor forms. Flavonoids such as Scutellarein, Pectolinarigenin and Naringin have reported to possess significant anti-cancer effects on different cancer cell lines till date. In this review, we provide a summary about the anti-cancer effect of the three flavonoids and its mechanisms of action that can be used in future for understanding their potent anti-tumor properties.
        4,000원
        4.
        2020.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The development of drugs from natural plant sources is at growing interest due to the limitations of chemical drugs in terms of side effects and cost-effective factors of natural medicines. Among the various components contained in natural plant materials, flavonoids are of increasing interest because of their extended biological benefits. Flavonoids are classified into various types according to their structure and possess different activities depending on the structure. In this study, the flavonoids contained in Artemisia, native to Korea were examined and reviewed. HPLC chromatograms of three Artemisia species (Artemisia annua L., Artemisia iwayomogi and Artemisia argyi H.) were examined from published sources and their component analysis by MS data were summarized. The various flavonoids of Artemisia were classified into 12 types according to the main structure, and 10 flavonoids based on various activities were examined. The 10 flavonoids were identified as quercetin, kaempferol, rhamnetin, diosmetin, luteolin, methoxyflavone, catechin, apigenin, malvidin and genkwanin with extensive reported studies till date. The ten flavonoids examined have been reported to be effective in preventing and treating various diseases and exhibit activities such as anti-cancer, anti-inflammatory, antioxidant, antiviral, anti-obesity, anti-diabetic and anti-Alzheimer. The collective results from the reported studies suggest that the three types of Korean native Artemisia, contains various flavonoids with beneficial activities and may have therapeutic effects against diseases.
        4,200원
        6.
        2019.04 구독 인증기관·개인회원 무료
        This study was carried out to confirm the predatory and developmental features of N. stenoferus. We determine the host range of N. stenoferus. As a result, it was confirmed that Aphis gssypii, Myzus persicae, Planococcus citri, and Frankliniella occidentalis. N. stenoferus is thought to be able to feed on other micro pests. The test for a developmental period of N. stenoferus at 25℃ showed that the egg period was about 10 days. The nymphal period was about 18 days. Each nymphal period from 1st instar to 3rd instar nymphs was about 3 days. And the nymphal period of 4th and 5th were about 3.5 and 6 days, respectively. The female adult laid eggs in stem tissue or on leaves, and sometimes on the soaked cotton for water supply.
        7.
        2019.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Inflammation is an important protective response mechanism that occurs against microbial invasion or injury. However, excessive inflammation may lead to cause of morbidity and mortality in diseases. The activated macrophages plays a vital role in inflammatory response by stimulation of lipopolysaccharide (LPS) and tumor necrosis factor-α (TNF-α). This activation further damages the host by inducing certain pro-inflammatory mediators such as nitric oxide (NO), interleukin-1β (IL-1β), interleukin- 6 (IL-6), TNF-α, inducible nitrous oxide (iNOS) and cyclooxygenase (COX-2). Flavonoids are bioactive compounds with potential effects as anti-cancer, anti-inflammation, anti-viral and anti-bacterial activities. Polymethoxyflavones (PMFs) are unique to citrus plants which are of specific interest owing to their biological effects that includes lipoprotein metabolism and anti-inflammatory activity. Sinensetin is one of the PMFs having five methoxy groups on the basic benzo-γ-pyrone skeleton with a carbonyl group at the C4 position. Sinensetin have been known for exerting various pharmacological activities including anti-angiogenesis, anti-diabetic and anti-inflammatory activities. However, there are no studies focused on the anti-inflammatory effects of sinensetin on skeletal muscle cells. In the present study, we investigated the antiinflammatory effect of flavonoids isolated from Sinensetin on the production of pro-inflammatory mediators mediated by nuclear factor-kappa B (NF-κB) by inhibition of signal transduction in LPS - induced L6 skeletal muscle cells.
        4,000원
        9.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The microstructure observation of seed surface structure is needed for protocols of breaking dormancy of seeds with physical dormancy. The seeds of Rubus species are surrounded by a thick, hard endocarp; together, the seed and endocarp make up the stone. We evaluate stone characteristics of 18 species of Rubus through optical microscopic observation, and correlate different stone characteristics with endocarp thickness. As a result of stone size comparison, Rubus species were classified as big stones group including R. parvifolius and R. idaeus, small stones group including R. longisepalus var. longisepalus, R. corchorifolius and R. hirsutus, and middle stones group including rest of the species. The result of this study revealed that stone size and the endocarp thickness in Rubus species was various characteristics in each species. Furthermore stone size and stone weight were also well correlated endocarp thickness and result indicated that heavy stones had harder endocarp than lighter one. Thus from the result of this study it can be presumed that only one stone characteristic approach may be sufficient to estimate other characteristics in Rubus.
        4,000원
        10.
        2017.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The relationship of in vitro starch digestibility and gel strength was investigated at various concentrations (10-30%) of rice cultivars with different amylose contents (27.9, 17.9, and 5.2%). As the rice flour concentration increased, predicted glycemic index decreased, but gel strength increased regardless of amylose contents. Gel strength correlated strongly with amylose content, whereas in vitro starch digestibility was more highly affected by rice flour concentration than by amylose contents. Moreover, the impact of degree of gelatinization on in vitro starch digestibility of high amylose rice was also examined in terms of structural features and rheological properties. The digestion rate of fully gelatinized flour was 1.7 times higher than that of native flour, while the disrupted structure with a different gelatinization degree during starch digestion was visually demonstrated through the X-ray diffraction and molecular distribution analysis. The rice flour changed from an A-type to a V-type pattern and showed difference in crystalline melting. The low molecular weight distribution increased with increasing degree of gelatinization during starch digestion. The apparent viscosity also increased with degree of gelatinization. These results demonstrated that the starch digestibility of rice was more affected by concentration than by amylose content, as well as by the degree of gelatinization due to structural difference.
        4,000원
        12.
        2016.04 구독 인증기관·개인회원 무료
        Brachymystax lenok tsinlingensis (family Salmonidae), cold freshwater fish, is endemic to Asia. This species is currently distributed throughout Russia, Mongolia, China and the Korean Peninsula. B. lenok tsinlingensis in South Korea was severely affected by anthropogenic activities such as habitat destruction, agricultural run-off and water pollution, and hence this fish has recently been dramatically decreased in its population sizes and become now critically endangered. To recover the number of individuals of B. lenok tsinlingensis, stocking or translocation programs have been conducted continuously by local governments since 1970s. However, these programs made little effort to clarify populations that may have originated from stocked, translocated or introduced fish. An understanding of genetic characteristics of endangered populations is critical to develop effective conservation and restoration plans especially because genetic diversity ensues their future fate. Therefore, we assessed the “conservation status” of this species by estimating the level of genetic diversity and genetic structure among ten geographic populations including restored populations via reinforcement and supplementation. Also, we aimed to trace the genetic origins of the newly translocated population (Chiak) through a restoration practice program. Moreover, we inferred the phylogenetic relationships among Korean lenok populations as well as across the Northeast Asia. Two hundred eighteen individuals of B. lenok tsinlingensis were sampled from ten localities (Yanggu, Injae, Seorak, Bangtae and Hongcheon: North Han River basin; Pyeongchang, Chiak and Jeongseon: South Han River basin; Taebaek and Bonghwa: Nakdong River basin in South Korea). Based on mitochondrial DNA (mtDNA) control region and eight nuclear microsatellite loci, we found extremely low levels of within-population genetic diversity, which suggests small effective population sizes (Ne) within populations. For mtDNA control region, each population housed one, or at most, two haplotypes that are restricted to the respective localities, meaning that these ‘genetically unique’ lineages will be lost permanently if the local populations undergo extinction. The overall values of haplotype diversity (h) and nucleotide diversity (π) for the entire Korean population were 0.703 ± 0.024 and 0.021 ± 0.010, respectively. In the case of microsatellites, average number of alleles across the eight loci for the entire population was 9.1 and allelic richness (AR) per population ranged from 2.375 to 4.144 (mean = 3.104). The values of observed heterozygosity (HO) and expected heterozygosity (HE) were similar to each other [HO: 0.400 ~ 0.590 (mean = 0.518); HE: 0.407 ~ 0.608 (mean = 0.504)]. The inbreeding coefficient (FIS) values were generally low, ranging from 0.048 to 0.279. Consequently, the majority of the populations (except Yanggu and Pyeongchang) were not significantly deviated from Hardy-Weinberg equilibrium (HWE), suggesting random mating at these loci tested. In addition, we found that Korean lenok populations were significantly genetically isolated from each other, with private mtDNA haplotypes and microsatellite alleles, indicating limited gene flow among populations, strong effects of genetic drift due to small Ne, or a combination of both. The Mantel test of microsatellites revealed a significant correlation (r = 0.414, P = 0.04) between genetic and geographic distances for pairwise comparisons among the ten populations, while that of mtDNA showed a lack of correlation. Given the shared identical mtDNA haplotype and similar microsatellite allelic distributions between Chiak and Hongcheon populations, we suggest that the restored (introduced) Chiak population would be inferred to be genetically originated from Hongcheon population. Phylogenetic relationships among Northeast Asian populations showed that South Korean lineages have more recently diverged from China (Yellow River), than between North Korea and Russia. Although the phylogenetic relationship would be expected to be associated with geography, South-North Korea and China populations with a similar latitude was more phylogenetically closely related. These findings may suggest a possible scenario for the historical movements of B. lenok tsinlingensis in Northeast Asia during Last Glacial Maximum (LGM). It would be supported by the line of evidence that most lenok populations migrated to southward from Northern Asia such as Russia and Mongolia during LGM because the Korean Peninsula was landlocked as inland epoch and functioned as a southern shelter with Yellow River. For this reason, the Korean Peninsula is suggested to be an important geographical region for better understanding phylogenetic relationships and evolutionary histories of B. lenok tsinlingensis across the Northeast Asia. Despite large efforts made to develop several restoration programs in South Korea for B. lenok tsinlingensis, it is still unknown whether these past restoration efforts were successful or fruitless, mainly because of little attention paid to post-restoration monitoring research. Hence, there was a lack of their published official records. In the future, conservation and restoration projects of the Korean lenok populations should consider the genetic data for a better understanding of their ecological and evolutionary trajectories. And finally, we hope that our findings here can help inform on the future effective conservation and restoration plans for B. lenok tsinlingensis populatio ns in South Korea.
        14.
        2015.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study fabricated low thermal conductive polyacrylonitrile (PAN)-based carbon fibers containing cellulose particles while maintaining their mechanical properties. The high thermal conductivity of carbon fibers limits their application as a high temperature insulator in various systems such as an insulator for propulsion parts in aerospace or missile systems. By controlling process parameters such as the heat treatment temperature of the cellulose particles and the amount of cellulose added, the thermal and mechanical properties of the PANbased carbon fibers were investigated. The results show that it is possible to manufacture composite carbon fibers with low thermal conductivity. That is, thermal conductivities were reduced by the cellulose particles in the PAN based carbon fibers while at the same time, the tensile strength loss was minimized, and the tensile modulus increased.
        4,000원
        15.
        2013.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate spirometric lung pattern, respiratory function and degree of fatigue by lung function tests and fatigue tests of 39 elderly people in a care facility aged 65 and over. The respiratory function tests were used to the Spirovit SP-1 and fatigue tests were used modified Piper fatigue scale(mPFS). Regarding the respiratory function, the FVC was 1.41±0.36ℓ, the FVC % predicted was 69.10±14.98%, the FEV1 was 1.02±0.31ℓ, the FEV1 % predicted was 63.27±16.05%, the FEV1/FVC was 72.77±13.40%, and the fatigue score was 5.83±1.09. As for the spirometric lung pattern, 19 patients had a restrictive pattern(48.7%), followed by 11 with a mixed pattern(28.2%), 5 with an obstructive pattern( 12.8%), and 4 with a normal pattern(10.3%). Regarding the respiratory function and fatigue by spirometric lung pattern, the FVC and the FVC % predicted of patients with a normal pattern or an obstructive pattern were greater than other groups at a statistically significant level. As for the FEV1, that of patients with a normal pattern was significantly higher than others, and for the FEV1 % predicted, that of patients with a normal pattern or a restrictive pattern was significantly higher(p<.001). Fatigue score by patients with a normal pattern was significantly less than patients of other patterns(p<.001). Therefore, pulmonary physical therapy is considered necessary to improve respiratory function and fatigue degradation of elderly in a facility.
        4,000원
        16.
        2012.09 구독 인증기관 무료, 개인회원 유료
        Probiotics, enzymes, organic acids, oligosaccharides, antioxidants, and other functional materials are actively being explored as alternatives to antibiotics. Probiotics include live beneficial microorganisms that colonize the intestinal tract and competitively inhibit attachment and growth of harmful microbes. Probiotics also increase feed efficiency by assisting in nutrient absorption and digestion. The current study was conducted in order to evaluate the effect of a new probiotic, CS-A, as a dietary supplement of a fermented product on growth performance, feed intake, and feed conversion efficiency in broiler chickens, and to evaluate its value as an alternative for antibiotics used as a feed additive. Antibacterial and anti-inflammatory effects of CS-A were investigated in vitro and the in vivo effects of a constant concentration of supplemented CS-A on growth rate and feed efficiency were evaluated. In addition, the safety of CS-A was assessed by examination of common symptoms and mortality. Determination of minimal inhibitory concentration revealed an excellent antibacterial effect of CS-A. Cytotoxicity was low and anti-inflammatory effects were achieved at the effective concentration of CS-A. Supplementation with 0.1% CS-A resulted in a feed efficiency score of 1.84 in broilers, compared to 2.00 in the control group. There were no adverse clinical findings, necropsy findings, hematology, and altered serum biochemistry parameters, and no mortality. Thus, it is concluded that CS-A is safe and effective as a feed additive.
        4,000원
        18.
        2007.03 구독 인증기관 무료, 개인회원 유료
        The present study investigated the effects of follicle stimulating hormone (FSH) and human chorionic gonadotrophin (hCG) on the nuclear maturation of canine oocytes. Oocytes were recovered from mongrel female ovaries in various reproductive states; follicular, luteal or anestrous stage. Oocytes were cultured in serum-free tissue culture medium (TCM)-199 supplemented with various concentrations of FSH (Exp. 1: 0, 0.5, 1.0 or 10 IU) or hCG (Exp. 2: 0, 0.5, 1.0 or 10 IU) or both (Exp. 3: 1 IU FSH + 1 IU hCG) for 72 hr to determine the effective concentration of these hormones, and to examine their combined effect. After maturation culture, oocytes were denuded in PBS containing 0.1% (w/v) hyaluronidase by gentle pipetting. The denuded oocytes were stained with 1.9 μM. Hoechst 33342 in glycerol and the nuclear state of oocytes was evaluated under UV light. More (p<0.05) oocytes matured to MII stage when follicular stage oocytes were supplemented with 1 IU FSH (6.2%) compared with the control, 0.1 or 10.0 IU FSH (0 to 1.2%). Significantly higher (p<0.05) maturation rate to MII stage was observed in follicular stage oocytes supplemented with 1.0 IU hCG (7.2%) compared with the control or other hCG supplemented groups (0 to 1.5%). However, the combination of FSH and hCG did not improve the nuclear maturation rate of canine oocyte (2.4 %) compared with FSH (6.2%) and hCG alone (7.2%). In conclusion, FSH or hCG alone significantly increased the maturation of canine oocytes to MII stage.
        4,000원
        19.
        2018.10 서비스 종료(열람 제한)
        Background : The root of Angelica gigas Nakai is used as a traditional herbal medicine in Korea for the treatment of many diseases. Poor water solubility of the active compounds from A. gigas Nakai is a major obstacle to bioavailability. Methods and Results : This work aimed to enhance the solubility of active compounds by a chemical (viz. surfactant) and physical (HME, hot melt extrusion) crosslinking method (CPC) in A. gigas Nakai. Infrared fourier transform spectroscopy (FT-IR) revealed multiple peaks in extrudate solids representing new functional groups including carboxylic acid, alkynes and benzene derivatives. Differential scanning calorimetry (DSC) analysis of the extrudate showed lower glass transition temperature (Tg) and lower enthalpy (ΔH) [Tg: 43℃; ΔH: <6 (J/g)] compared to the non-extrudate (Tg 68.5℃; ΔH: 123.2) formulations. X-ray powder diffraction (XRD) analysis revealed amorphization of crystal materials in extrudate solid. In addition, enhanced solubility (53%), nanonization (403 ㎚), and higher amount of extracted phenolic compounds were achieved in the extrudate solid compared to non extrudate (36%, 1499 ㎚, respectively). Among the different extrudates, acetic acid and span 80 mediated formulations showed superior extractions efficiency. Conclusion : We conclude that the HME successfully enhanced the production of amorphous nano dispersions of phenolic compound including decursin from extrudate solid formulations. human dermal fibroblasts, which is, associated with the regulation of procollagen biosynthesis resulting from AMRP-induced TGF-β1 expression and the mitogenic activity in HDF cells, and therefore, is expected to reduce the age-dependent loss of extracellular matrix proteins.
        20.
        2018.08 KCI 등재 서비스 종료(열람 제한)
        Background: The root of Angelica gigas Nakai is used as a traditional herbal medicine in Korea for the treatment of many diseases. However, the poor water solubility of the active components in A. gigas Nakai is a major obstacle to its bioavailability. Methods and Results: This work aimed at enhancing the solubility of the active compounds of A. gigas Nakai by a chemical (using a surfactant) and physical (hot melt extrusion, HME) crosslinking method. Fourier transform infrared spectroscopy revealed multiple peaks in the case of the extrudate solids, attributable to new functional groups including carboxylic acid, alkynes, and benzene derivatives. Differential scanning calorimetry analysis showed that the extrudate soilid had a lower glass transition temperature (Tg) and enthalpy (ΔH) (Tg : 43℃, ΔH : < 6 J/g) as compared to the non-extrudate (Tg : 68.5℃, ΔH : 123.2) formulations. X-ray powder diffraction analysis revealed the amorphization of crystalline materials in the extrudate solid. In addition, enhanced solubility (53%), nanonization (403 ㎚), and a higher amount of extracted phenolic compounds were achieved in the extrudate solid than in the non-extrudate (solubility : 36%, nanonization : 1,499 ㎚) formulation. Among the different extrudates, acetic acid and span 80 mediated formulations showed superior extractions efficiency. Conclusions: HME successfully enhanced the production of amorphous nano dispersions of phenolic compound including decursin from extrudate solid formulations.
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