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        검색결과 9,512

        4841.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국산 애기버섯벌레과(Ciidae, Leach)에 속한 애기버섯속(Cis Latreille) 분류학적으로 검토하였다. 이 속에 속한 Cis boleti (Scopoli, 1763); Cis seriatopilosus Motschulsky, 1861; Cis mikagensis Nobuchi & Wada, 1955; Cis jezoensis Nobuchi, 1960; Cis sasajii Kawanabe, 2001; Cis hieroglyphicus Reitter, 1877 등 6종을 국내에서 처음으로 분류학적으로 검토하여 보고하였다. 또한 야외관찰과 실내사육을 통해 6종에 대한 숙주버섯을 처음으로 밝혀 보고 하였다. 따라서 이번 연구에서는 한국산 애기버섯벌레속에 대한 분류학적 정보와 더불어 한국산 종들의 숙주버섯에 대한 생태적 정보를 제공하였다.
        4,000원
        4842.
        2013.03 구독 인증기관 무료, 개인회원 유료
        To investigate the effects of co-solvents on the morphology of nano-scale zein materials, zein solutions were electrospun with different co-solvent ratios of EtOH/H2O. Different zein solution concentrations were used to study the effects of the zein content on the electrospun materials. The resulting electrospun materials were all characterized using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The diameters of the electrospun nanoparticles and nanofibers were found to increase when increasing the EtOH ratio at certain zein concentrations. Furthermore, increasing the zein content changed the morphology of the electrospun materials from nanoparticles to nanofibers.
        4,000원
        4843.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oil spills have occurred throughout the years of industrialization and represent a global challenge as they affect vast areas of the ocean. The toxicity of crude oil to aquatic organisms has been extensively investigated, but the potential impacts of crude oil on vertebrate development remain largely unknown. Here, we investigated the effects of dispersants used in treating a recent oil spill, as well as that of crude oil, on vertebrates by using the zebrafish (Danio rerio) model species, which has been widely used in empirical studies of both early embryonic development and adult physiology. Chronic exposure to crude oil resulted in marked developmental abnormalities, including pericardial edema, abnormal trunk vessel development, retardation of axonal branching, and abnormal jaw development. Embryonic development was affected more severely by exposure to the oil-dispersant combination than to the oil alone. Thus, the zebrafish in vivo model system suggests that dispersant treatment can have detrimental developmental effects on vertebrates and its potential impact on marine life, as well as humans, should be carefully considered in clean-up efforts at the site of an oil spill.
        4,000원
        4844.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Algal blooms in potable water supplies are becoming an increasingly prevalent and serious water quality problem around the world. In addition to precipitating taste and odor problems, blooms damage the environment, and some classes like cyanobacteria (blue-green algae) release toxins that can threaten human health, even causing death. There is a recognized need in the water industry for models that can accurately forecast in real-time algal bloom events for planning and mitigation purposes. In this study, using data for an interconnected system of rivers and reservoirs operated by a New Jersey water utility, various ANN models, including both discrete prediction and classification models, were developed and tested for forecasting counts of three different algal classes for one-week and two-weeks ahead periods. Predictor model inputs included physical, meteorological, chemical, and biological variables, and two different temporal schemes for processing inputs relative to the prediction event were used. Despite relatively limited historical data, the discrete prediction ANN models generally performed well during validation, achieving relatively high correlation coefficients, and often predicting the formation and dissipation of high algae count periods. The ANN classification models also performed well, with average classification percentages averaging 94 percent accuracy. Despite relatively limited data events, this study demonstrates that with adequate data collection, both in terms of the number of historical events and availability of important predictor variables, ANNs can provide accurate real-time forecasts of algal population counts, as well as foster increased understanding of important cause and effect relationships, which can be used to both improve monitoring programs and forecasting efforts.
        4,000원
        4845.
        2013.03 구독 인증기관 무료, 개인회원 유료
        We describe the preparation of superparamagnetic nanoclusters (SNCs) by fine-tuning of the seed Fe3O4 nanoparticle sizes to enhance and their T2 relaxivity can be increased by > 4-fold. Therefore, with 11 nm seed core and PVA coating, SNC-11 exhibit a higher T2 relaxivity than other cluster condition. So fabricating the cluster, seed size is the most important influence the T2 relaxivity. As well as, in vitro cellular imaging results demonstrated the strong potential of SNCs for clinical applications by targeting affinity. According to the experiments, with 11 nm seed core and PVA coating, SNC-11 exhibited the highest T2 relaxivity of 454 mM-1s-1 due to the strong seed size effect on their magnetic sensitivity, indicating superior magnetic resonance (MR) contrast efficiency. Further in vitro cellular imaging results demonstrated the strong potential of SNCs for clinical applications.
        4,300원
        4846.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purposes of this study were to develop a new orthosis controlling ankle and knee joint motion during the gait cycle and to identify the effects of the newly designed orthosis on gait kinematics and tempospatial parameters, including coordination of the extremities in stroke patients. Fifteen individuals who had sustained a stroke, onset was 16 months, participated in this study. Before application of the measurement equipment the subjects were accustomed to walking on the ankle-foot orthosis (AFO) or stance control knee with knee flexion assisted-oil damper ankle-foot orthosis (SCKAFO) for 5 minutes. Fifteen patients were investigated for 45 days with a 3-day interval between sessions. Measurements were walking in fifteen stroke with hemiparesis on the 3D motion analysis system. Comparison of AFO and SCKAFO are gait pattern. The difference between the AFO and SCKAFO conditions was significant in the gait velocity, step length of the right affected side, stance time of both legs, step-length asymmetry ratio, single-support-time asymmetry ratio, -thigh angle and -shank angle in the mid swing (p<.001). Using a SCKAFO in stroke patients has shown similar to normal walking speeds can be attained for walking efficiency and is therefore desirable. In this study, the support time of the affected leg with the SCKAFO was longer than with the AFO and the asymmetry ratio of single support time decreased by more than with the AFO. This indicates that the SCKAFO was effective for improving gait symmetry, single-support-time symmetry. This may be due to the decrease of gait asymmetry. Thus, the newly designed SCKAFO may be useful for promoting gait performance by improving the coordination of the extremity and decreasing gait asymmetry in chronic stroke patients.
        4,000원
        4847.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of axillary crutch length on trunk muscle activity and lumbo-pelvic-hip complex movements during crutch gait. Eleven healthy men participated in this study. The participants performed a three-point gait with optimal, shorter, and longer crutch lengths. Weight-bearing (WB) side was determined as the dominant leg side. The electromyography (EMG) activity of the bilateral rectus abdominis (RA) and erector spinae (ES) muscles and lumbo-pelvic-hip complex movements were monitored using a three-dimensional motion system with wireless surface EMG. Differences in the EMG activity of RA and ES muscles and range of motion (ROM) of lumbar spine, pelvis, and hip among conditions were analyzed using one-way repeated-measures analysis of variance, and a Bonferroni correction was conducted. There was less RA muscle activity on the WB side under the optimal crutch length condition compared with shorter and longer crutch length conditions (p<.05). The EMG activity of the RA muscle on the non-WB side and ES muscle on the WB side were significantly decreased under the optimal crutch length condition compared with shorter crutch length condition (p<.05). No significant differences in the EMG activity of the ES muscle on the non-WB side and ROM of lumbo-pelvic-hip complex were found among conditions (p>.05). These findings indicate that the optimal crutch length improves the trunk muscle efficiency during crutch gait.
        4,000원
        4848.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to compare the immediate effects of upper trapezius muscle stretching in more tensed position (MTP) and less tensed position (LTP) on the change of range of motion (ROM) for neck rotation, and the ROM for conjunct neck motions at end-range of neck rotation toward the painful side in patients with unilateral neck pain. Eighteen patients with unilateral neck pain were recruited for the study's MTP group, and 18 age-, weight- and gender-matched patients with unilateral neck pain were recruited for LTP group. The ROM changes in active neck primary and conjunct motions were measured using a cervical ROM inclinometer in the sitting position. Our results showed that both upper trapezius stretching method in MTP and LTP were significantly effective in increasing the ROM of neck rotation toward painful side in patients with unilateral neck pain. However, a significantly greater increase in the ROM for neck rotation and a further decrease in conjunct neck extension during neck rotation toward the painful side were shown in MTP group, compared to LTP group. The upper trapezius stretching in MTP is useful in increasing the ROM of neck rotation and decreasing the range of conjunct neck extension during neck rotation toward the painful side in patients with unilateral neck pain.
        4,000원
        4849.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 농업유전자원센터에 보존되어있는 불가리아 재래종 고추 유전자원 61 점을 대상으로 농업형질을 조사하고, 22개의 분자마커(SSR marker)를 이용하여 불가리아 재래종 고추 유전자원의 유전적 다양성 및 집단분석을 통하여, 자원보존 및 효율적인 작물 육종을 위한 기초정보를 제공하고자 본실험을 수행하였으며 결과는 다음과 같다. 1. 파종 후 발아까지 소요일수는 최소 11일에서 최대 26 일,평균 16.9 일이었고 개화 소요일수는 최소 48일, 최대 65일, 평균 56.9일이었으며 성숙까지의 소요일수는 최소 73일, 최대 98일, 평균 90.7일이었다. 2. 농업형질의 특성을 바탕으로 PCA 분석을 이용하여 불가리아 고추의 다양성을 분석한 결과, 파종 후 개화까지의 소요일수에 따라 조생종, 중생종, 만생종 3개의 그룹으로 나눌 수있었다. 3. 61점의 고추자원에 대하여 22개 SSR 마커에 의해 나타난 대립유전자 (allele)수는 총 82개였다. 마커당 평균 allele수는 3.7 개였고, allele 수의 범위는 2개에서 5개로 확인되었다. 유전적 다양성을 나타내는 PIC 값의 범위는 0.061-0.636이었으며 평균 PIC 값은 0.349로 확인되었다. 4. 분자마커(SSR)를 이용하여 UPGMA, PCoA, STUCTURE 분석을 통한 고추의 다양성 및 집단 구조를 분석한 결과, 3개의 그룹으로 나뉘어졌다. 결론적으로, 농업형질 특성을 바탕으로 한 불가리아 재래종고추의 다양성과 분자학적 특성을 이용한 다양성 결과와는 차이가 있었다.
        4,000원
        4850.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A simple and sensitive analytical method was developed using gas chromatography with electron capture detector (GC-ECD) and gas chromatography-mass spectrometry (GC-MS) for determination of Picoxystrobin in agricultural products (apple, hulled rice, mushroom, pepper, soybean, and mandarin). Picoxystrobin residues were extracted with acetonitrile, partitioned with saline water, and then they were cleaned up on a florisil solid-phase extraction (SPE) cartridge to obtain an extract suitable for analysis by GC-ECD and GC-MS. The method was validated using 6 agricultural product samples spiked with Picoxystrobin at different concentration levels (0.02, 0.05 and 0.5 mg/L). Average recoveries of Picoxystrobin (using each concentration three replicates) ranged 64.0~98.3% with relative standard deviations less than 10%, calibration solutions concentration in the range 0.1~5 mg/L, and limit of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.02 mg/L, respectively. The result showed that the developed analytical method is suitable for Picoxystrobin determination in agricultural products.
        4,000원
        4851.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The language threshold effect on comprehending an L2 (second language) text was experimentally examined, using two types of measurement tool, multiple-choice & true/false questions and a recall task for L2 reading comprehension. Cognitive processes implicated in each measure were delineated to allow a finer analysis on the role of L1 reading competence and L2 proficiency in comprehending an L2 text. In order to observe how one aspect of L2 proficiency, vocabulary knowledge, is related to language threshold effect, thirty-two 9th grade Korean students in Korea were given a vocabulary knowledge acquisition activity in a treatment condition between a pretest and a posttest. The relative contributions that L1 reading competence and L2 proficiency made to L2 reading comprehension were analyzed before the treatment and after the treatment using multiple-regression analysis technique. The findings of this repeated measure design were consistent with previous correlational studies showing that the role of L1 reading competence became stronger as L2 proficiency operationalized via vocabulary knowledge improved. What is elaborated in the present study is the fact that cognitive processes, initiated by a recall task, are more sensitive to the weakening of language threshold effects.
        5,700원
        4852.
        2012.12 구독 인증기관 무료, 개인회원 유료
        Skin-derived precursor cells (SKPs) are multipotent, sphere-forming and embryonic neural crest‐related precu- rsor cells that can be isolated from dermis. It is known that the properties of porcine SKPs can be enhanced by leuke- mia inhibitory factor (LIF) which is an essential factor for the generation of embryonic stem cells in mice. In our pre- sent study, to enhance or maintain the properties of murine SKPs, LIF was added to the culture medium. SKPs were treated with 1,000 IU LIF for 72 hours after passage 3. Quantitative real time RT‐PCR was then performed to quantify the expression of the pluripotent stem cell specific genes Oct4, Nanog, Klf4 and c‐Myc, and the neural crest specific genes Snai2 and Ngfr. The results show that the expression of Oct4 is increased in murine SKPs by LIF treatment whereas the level of Ngfr is decreased under these conditions. Interestingly, LIF treatment reduced Nanog exp- ression which is also important for cell proliferation in adult stem cells and for osteogenic induction in mesenchymal stem cells. These findings implicate LIF in the maintenance of stem- ness in SKPs through the suppression of lineage differen- tiation and in part through the control of cell proliferation.
        4,000원
        4853.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        RNAi 기법은 예쁜꼬마선충을 비롯하여 초파리, 생쥐, 인체및 식물들을 포함한 다양한 생물종에서 작용기작이 잘 알려져 있고, 특정 유전자들의 발현을 제어하기 위해 사용되어 왔다.본 논문은 RNAi 기법을 통해 구축된 뿌리혹선충 저항성 형질전환식물체들의 개발현황, 발전 및 응용 가능성에 대해 고찰하고자 하였다. 지난 10여년에 걸쳐 진행된 연구들을 통해 다양한 분화단계의 뿌리혹선충으로부터 분석된 79,978개의 EST가 GenBank에등록되었고, 고구마뿌리혹선충(M. incognita)과 당근뿌리혹선충(M. hapla)의 전체 게놈 염기서열이 해독됨으로써 뿌리혹선충의 기생에 관련된 단백질들 및 식물세포벽 분해 관련 효소들에 대한 정보를 이용할 수 있게 되었다. RNAi의 기본 기작은 모든 진핵생물종에서 잘 보존되어 있고, 최근 식물기생선충들에서 RNAi 효과에 대한 연구결과들이 많이 발표되었다. 서로 다른 뿌리혹선충들에서 현재까지 22종 이상의 RNAi를위한 목표 유전자들이 보고되었다. 제2령 식물기생선충(second-stage juvenile of plant parasitic nematodes)에게dsRNA의 섭취를 유도하는 octopamine, resorcinol, serotonin등의 화합물들이 발견되었고, 이를 이용하여 선충 유전자의 발현제어를 쉽게 판별할 수 있는 새로운 기술의 활용이 가능하게 되었다. 최근에 RNAi 기술의 응용 및 발전을 통해 형질전환식물체에서 발현된 dsRNA에 의한 식물기생선충 유전자들의 발현제어가 증명되었고, 이를 위한 핵심 요소들로서 적절한 선충 표적 유전자의 선택, 식물체 내 높은 함량의 dsRNA의 발현 및선충이 섭취할 수 있는 충분한 양의 dsRNA의 운반 등이 중요하다는 것이 밝혀졌다. 특히, 비표적 유전자서열(off-target gene sequence)의 발현제어를 피하기 위해 다음과 같은 사항들이 고려되어야 한다. 1)비표적 유전자서열을 확인할 수 있는 소프트웨어의 개발 및 이를 통한 비표적 유전자서열을 제거한 RNAi 벡터를 제작하여야 한다. 2)식물과 동물에서 상동성이 높은 표적 유전자의 발현을 피해야 한다. 3)전사해석틀(open reading frames)의 염기서열들 보다 상동성이 낮은 5' 혹은 3'-비해석부위(untranslated regions)로부터 표적 유전자를설계하여야 한다.
        4,000원
        4854.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 세계 26개국에서 도입된 녹두 유전자원 705점에 대하여16개의 형태적 형질 특성을 이용하여 각각 두 가지의 군집방법, 핵심집단 자원수 결정방법 및 표본추출 방법을 조합하여 총8개의 핵심집단(SUNPR, SUNPPr, UNPR, UNPPr, SUNLR, SUNLPr, UNLR, UNLPr)을 작성하여 원수집단과 비교한바 8개핵심집단 모두 원수집단과는 분산과 평균치에서 차이가 없었다. 2. Nei의 다양성지수는 8개 핵심집단 모두 원수집단 보다높았고, 특히 UNLPr이 가장 높았으며, UNPR은 다른 핵심집단에 비하여 상대적으로 낮은 지수를 보였다. 3. 원수집단과 핵심집단간 자원분포의 동질성을 파악하기 위하여 카이자승 검증을 한 결과 12개 양적형질과 1개의 질적형질(종피색)은 모든 핵심집단이 동질분포를 보였으나 3개의질적 형질 (배축색, 종피광택, 생육습성)은 핵심집단에 따라서동질분포를 하는 것과 그렇지 않은 것이 있었으며, 8개 핵심집단 중 UNPPr은 동질성이 가장 높았다. 평균차율(MD%)과일치율(CR%)은 8개 핵심집단 모두 유의한 수준을 보였다. 4. 8개의 모든 핵심집단이 원수집단과 평균치에서 차이가 없고, 높은 다양성을 과 동질한 분포를 보이며, 평균차율(MD%)과 일치율(CR%)이 유의한 수준을 보여 원수집단의 다양성을잘 나타내는 것으로 해석되었다. 5. 핵심수집단 크기(10%와 15%)에 따른 다양성은 유의한차이가 없었으며, 8개의 핵심집단 중 평균치, 동질분포, 일치율 및 도복내성을 고려할 때 UNPPr이 가장 좋은 핵심집단으로 사료되었다.
        4,300원
        4855.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the in vitro fermentation parameters of whole crop barley (WCBS-TMR) and Italian ryegrass (IRGS-TMR) silage total mixed rations were compared. A rice straw based diet (RSBD), which was a mixture of rice straw and concentrate (60:40), was used as the control. The feeds were incubated in buffered rumen fluid for 3, 6, 9, 12, 24, 48 and 72 hours at 39°C. At the end of each incubation period the following parameters were determined, total gas, pH, ammonia nitrogen (NH3-N), volatile fatty acids (VFA) and then the acetate to propionate ratio (A/P) was calculated. The dietary treatments did not affect (p>0.05) the overall production of NH3-N, gas, total VFA and all the individual VFA, with the exception of n-butyrate (p<0.001). The treatment diets significantly affected the A/P ratio (p<0.01). The control diet resulted in the lowest A/P ratios, followed by WCBS-TMR and lastly IRGS-TMR had the highest ratios. Gas production was not different between treatments, suggesting a probable similar level of digestibility when treatments are fed to animals. It can therefore be concluded from the present study that WCBS and IRGS are of almost an equivalent nutritional value when incubated in a TMR form. WCBS-TMR however resulted in lower A/P ratios than IRGS-TMR, which is indicative of a more energy efficient diet.
        4,000원
        4856.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to develop persimmon peel, a by-product of dried persimmon manufacturing, as a feed additive via lactic acid bacteria fermentation. Pediococcus pentosaceus, Lactobacillus plantarum, and three strains of Leuconostoc mesenteroides were used as a starter culture in the solid state fermentation of persimmon peel, and antioxidant activity and total polyphenol content were assessed. Leuconostoc mesenteroides KCTC 3100 showed high antioxidant activity (p<0.05), whereas Pediococcus pentosaceus showed high total polyphenol content (p<0.05). These two strains were thus selected as starter culture strains. Glucose, sucrose and molasses were used as variables for optimization and a total 15 experimental runs were produced according to Box-Behnken design. Regarding significant effects of variables, molasses showed linear and square effects on antioxidant activity of persimmon peel fermentation (p<0.05). In conclusion, optimum concentrations of glucose, sucrose, and molasses were determined to be 4.2, 3.9 and 5.3 g/L, respectively, using a response surface model. Antioxidant activity was also improved 2.5 fold after optimization.
        4,000원
        4857.
        2012.12 구독 인증기관 무료, 개인회원 유료
        To identify subspecies of the sika deer, Cervus nippon, and to select C. n. hortulorum individuals for restoration of this subspecies in Korea, we obtained cytochrome b partial sequences (375 bp) of sika deer (C. nippon) from deer farms in northeastern China, North Korea, mainland Korea, and Jeju Island. Based on noninvasive samples, these cytochrome b sequences were compared with the corresponding haplotypes of sika deer, which were obtained from GenBank. We identified five individuals of sika deer from deer farms in northeastern China and North Korea as C. n. hortulorum, and found that interbreeding between individuals belonging to different subspecies is common on deer farms in far-eastern Asia. We concluded that the five C. n. hortulorum individuals on deer farms from northeastern China and North Korea, detected in this study, cannot be considered as pure descendants of C. n. hortulorum in the wild.
        3,000원
        4859.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It has been known that endophyte (Neotyphodium coenophialum) is beneficial to tall fescue (Schedonorus phoenix Scop.) because the mutualistic endophyte is able to confers tolerance against abiotic and biotic stresses to tall fescue. However, this fungal endophyte produces toxic alkaloid resulting in negative effects on animal performance. Recently, Non-toxic endophyte have been developed and inserted into tall fescue to avoid detrimental effect on animal but remaining positive influence on tall fescue. In order to keep this beneficial impact, it is essential to have endophyte infected tall fescue through vertical transmission from maternal plants to seeds. Little research has been carried out on endophyte transmission. To get basic information related to endophyte transmission, experiment was conducted to examine the effect of plant genotype on endophyte transmission under water stresses. Overall endophyte concentration in seeds was higher than that in panicles and endophyte concentration in seeds and panicles relied on plant. This study revealed that drought is not a critical component to control the endophyte transmission from maternal plants to seeds. Plant genotype is an important factor controlling the endophyte transmission from plant to seed.
        4,000원
        4860.
        2012.12 구독 인증기관 무료, 개인회원 유료
        Although bombesin (BN) regulates colonic motility, the associated mechanism of action remains unclear. The objective of this study was to investigate the effect of BN on colonic motility using isolated rat colon. An isolated rat colon was perfused with Krebs solution via the superior mesenteric artery. Intraluminal pressure was measured via microtip catheter pressure transducers at both proximal and distal portions of the isolated colon. After a control period, BN was administered intraarterially in concentrations of 13, 26, 130, and 260 pM. After pretreatment with hexamethonium (10-3 M), atropine (10-5 M), or tetrodotoxin (10-6 M), BN was administered at a concentration of 260 pM (proximal colon) or 130 pM (distal colon); intraluminal pressure was then monitored. Changes in motility were expressed as the percentage change of motility index (MI) over the basal period. As a result, BN increased colonic motility and a dose-dependent increase in proximal colonic motility was observed. The stimulant effect of BN was almost completely abolished by atropine and tetrodotoxin at both the proximal and distal colon. However, BN was not inhibited by hexamethonium at both the proximal and distal colon. Therefore, the stimulant action of BN may be mediated by local cholinergic muscarinic receptors.
        4,000원