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        검색결과 103

        23.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to investigate the effect of an aluminum chromium nitride (AlCrN) coating on tool wear and hole quality in the conventional drilling process of carbon fiber-reinforced plastic (CFRP) composites, titanium alloy (Ti), and CFRP–Ti stack workpieces popular in the aerospace industry. The advanced arc plasma acceleration (APA) method of physical vapor deposition (PVD) was used for all AlCrN coatings. The drilling experiments were conducted with uncoated drills as well as AlCrN-coated drills. When drilling CFRP only, the AlCrN coating was removed at the drill cutting edges and the margin area, which suggests the carbon fibers abraded the coatings. When drilling Ti only, the AlCrN-coated drill mitigated the Ti adhesion formation, which resulted in less tool wear. In addition, hole quality for both CFRP and Ti was improved when the coating was used versus the uncoated tool. The machinability of CFRP–Ti stacks in the drilling process was improved by utilizing the advanced AlCrN coating on the WC tool in terms of drilling forces and hole quality parameters such as average hole size, average hole roundness, hole surface roughness, and Ti exit burr height.
        4,200원
        26.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to evaluate of black carrot on the antioxidant activity and quality characteristics of Sulgidduk. Sulgidduk was prepared with different amounts (0, 1, 2, 3, 4%) of black carrot. As the amount of added black carrot increased, the moisture content (p<0.05) and pH were decreased (p<0.001). Sugar content results showed the increase with the addition of black carrot (p<0.01). L (lightness) values and b (yellowness) values decreased whereas a (redness) values increased with an increased concentration of black carrot powder (p<0.001). The mechanical texture of Sulgidduk was decreased by the addition of black carrot considering hardness, chewiness and gumminess (p<0.001) while those of springiness, cohesiveness increased. Consumer acceptability test revealed that the 2% black carrot groups had a higher score than the other groups in respect to color, flavor, taste, texture, overall palatability. To examine antioxidant activities of Sulgidduk, total phenolic, DPPH radical scavenging activity, and total anthocyanin were tested. Total phenolic, DPPH radical scavenging activity, and total anthocyanin showed good vitality as amounts of black carrot powder increased (p<0.001). Based on the various aspects of results, 2% of black carrot added into Sulgidduk showed the best functionality and sensory qualities.
        4,000원
        30.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Amniotic membrane stem cells are considered as a good alternative to embryonic stem cells, but their use in clinical studies is still not common. Here, exosomes from canine amniotic membrane mesenchymal stem cells (cAmMSCexo) were used for dog sperm cryopreservation. Upon cryopreserved straws using cryoprotectant containing 0, 0.5, 1, or 2 μg/mL of cAmMSC-exo were thawed, motility and membrane integrity were analyzed. However, results showed no significant differences between the groups. We concluded that cAmMSC-exo with lower than 2 µg/mL have no effects on sperm cryopreservation, and further studies to get higher concentrations of cAmMSC-exo should be conducted for clinical application.
        4,000원
        31.
        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
        32.
        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
        33.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A new discrete bis-dithiolene complex, [ PPh4]2[Zn(DMED)2] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate) with sulfurbased radical character was synthesized and structurally characterized. Complex 1 is stable and exhibits a square planar geometry around the zinc metal. 1 forms nanospheres through a one-pot water-induced self-assembly in a mixture of solvents (acetonitrile–water). These nanospheres were further decorated with water-soluble carbon nanotubes (wsCNTs) through hydrogen bonding between the peripheral –COOCH3 groups of 1 and surfacial carboxyl groups of wsCNTs to assemble into a spherical nanocomposite. The as-prepared nanocomposite showed fluorescence emissions in visible region due to the separation of energy states of the nanospheres assisted by wsCNTs, suggesting the future possibilities of these new materials for use in biomedical application.
        4,000원
        34.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was designed to determine the effect of barn or cycle of grazing on changes of biochemical metabolites in prepartum and changes of milk composition in postpartum of dairy cows. For this purpose, a total of sixteen 25 months old Holstein primiparous dairy cows were allocated in two groups (n=8) with an average body weight of 571.61 ± 35.30 kg (Barn) and 578.10 ± 39.20 kg (Grazing). The study was conducted from June 2018 to October 2018. Results revealed that barn raised dairy cows had a higher increase in their serum albumin and calcium level on day 14 prepartum. However, the level of palmitic acid, saturated fatty acid increased significantly, and the level of fat, oleic acid, γ-linoleic acid, arachidonic acid and unsaturated fatty acids decreased significantly in barn raised dairy cow’s milk on day 14 postpartum. There were no significant differences observed with respect to all other biochemical metabolites, fatty acids and minerals between barn raised and cycle grazing dairy cows during prepartum and postpartum. Our study results could serve to a better understanding of barn raised cow with respect to changes of biochemical metabolites in prepartum and changes of milk composition, fatty acids and minerals content in grazing dairy cows in postpartum for estimating their physiological status.
        4,000원
        37.
        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
        39.
        2018.10 구독 인증기관·개인회원 무료
        기후변화와 세계시장 개방에 따른 외래 및 돌발해충의 종류는 다양해지고 밀도는 지속적으로 증가하고 있지만 발생 실태에 관한 자료는 미흡하다. 본 연구는 경상지역 돌발 및 남방계 해충의 발생과 피해조사를 위해 미국선녀벌레, 갈색날개매미충, 꽃매미 등 돌발해충 6종을 경남 9시군과 경북 9시군에서 월동기 1회, 약충기 2회, 성충기 1회를 순회 조사하였고, 애멸구, 배추좀나방, 볼록총채벌레 등 남방계 해충 5종을 산간지, 중산간지, 평야지 각 3지역에서 10일 간격으로 조사하였다. 돌발해충인 꽃매미와 갈색날개매미충 월동난 발생현황으로 농경지 발생면적은 2017년 비해서 2018년도에 발생면적이 늘었으나 발생 농가수는 줄어들어 발생지역은 점차 확대해가고 있으나 발생밀도는 줄어드는 것으로 조사되었다. 해충별 조사결과로 미국 선녀벌레 약충이 함안에서 가장 밀도가 많이 조사되었고, 함양, 상주, 예천 둥에서 발생하였고, 갈색날개매미충 약충은 하동에서 가장 발생이 많았고 진주, 사천, 고성, 산청, 함양, 거창, 상주, 예천 등에서 넓게 발생하였으나 꽃매미 약충은 함안과 함양에서만 조사되었다. 고도별 발생 차이는 발생밀도가 적어서 알 수가 없었다. 갈색여치는 조사지역 모두에서 발생을 확인하지 못했고 먹노린재는 하동에서만 일부 조사되었고 나머지 지역에서는 확인하지 못했다. 목화진딧물은 조사지역간에 밀도 차이가 많았고 고도에 따른 차이보다는 농가에서 농작물 재배관리나 조사 시기에 따른 차이로 보인다. 애멸구의 월동기 조사와 육안조사 결과 발생밀도가 낮았고, 볼록총채벌레는 트랩조사 결과 조사지역 감나무에서 모두 발생하였으나 발생밀도는 높지 않았고 7월중 밀도가 함양에서 평균 9.8마리로 가장 높았다.
        40.
        2018.05 구독 인증기관·개인회원 무료
        This research evaluates the applicability of ponded ash in the production of backfill material. From various ponded ash/sand ratios, cement, and air foam conditions, test specimens were developed to investigate many engineer properties of backfill material. Then, the falling weight deflectometer and excavation tests were carried out to determine the behavior of the material in the actual testbed. The test results suggested that all mixtures achieved optimal flowability performance with acceptable stiffening time. It is indicated that the compressive strength increased as ponded ash and cement contents increased, but the strength decreased with an increase in air-foam content or number of freeze-thaw cycles. From the testbed results, it was found that utilizing 100% ponded ash in the production of backfill material is very promising for sustainable development purpose.
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