• 한국임상수의학회지
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• 제25권3호
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• pp.165-169
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• 2008

Renal ischemia-reperfusion (I/R) injury is great clinical important because viability of the organ depends on the tolerance to ischemia-reperfusion injury, an inevitable processing during surgery. The purpose of this study was to investigate the effects of premedicated ascorbic acid alone in I/R injury model induced by cross-clamping of renal vessels. In the rabbit models, 2-4 kg New Zealand white rabbits were subjected to 30 minutes of warm unilateral renal ischemia followed by removal of contralateral kidney and then divided into five groups, control (2) arid treatment groups (3). In control group 1, the rabbits only received right nephrectomy. In control group 2, the rabbits received I/R on left kidney after the right nephrectomy. In treatment group 1, the rabbits received ascorbic acid 50 mg/kg IV before the operation. In treatment group 2, the rabbits received ascorbic acid 100 mg/kg IV before the operation. In treatment group 3, the rabbits received ascorbic acid 200 mg/kg IV before the operation. Blood samples were collected from these rabbits for measurement of kidney function tests at the 0, 1 st, 3rd and 7th day and antioxidant enzyme( SOD, GSHPx, CAT) at 24 hours. Kidney function tests (serum creatinine and BUN) showed a significant difference between group 2 and group 4, 5. Activity of antioxidant enzymes in plasma were significant decrease in group 4, 5 compare to group 2. The result of this study suggested that the exogenous ascorbic acid had a role of attenuation of renal I/R injury in rabbit model.

• 동의신경정신과학회지
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• 제14권1호
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• pp.27-44
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• 2003

Objective : The aim of this study was to assess protective effects of Whangryonhaedoktang on the chronic mild stress (CMS) animal model of depression. Method : Male Sprague-Dawley rats were used for this study. The subjects were divided into 3 groups (CMS-drug group: Whangryonhaedoktang was administered during CMS procedure, CMS-vehicle: water was administered during CMS procedure, normal control group: without CMS procedure). After 4 weeks of CMS procedure, Morris water maze (MWM) test and open field test were executed and tyrosine hydroxylase (TH) was measured in ventral tegmental area (VTA) and locus coeruleus (LC) of rat brain. Result : 1. CMS procedure induced defects of spatial learning in early period of MWM test. 2. CMS Whangryonhaedoktang group showed shorter escape latency in comparison with CMS control group in MWM test on the first day of the test. 3. CMS Whangryonhaedoktang group and CMS control group showed no significant difference of activities and emotional behaviors in comparison with normal control group in open field test. 4. CMS Whangryonhaedoktang group showed significant inhibition effects of TH expression in VTA and LC areas in comparison with CMS control group. Conclusion : These results suggest that Whangryonhaedoktang may have inhibition effects to early period defects of spatial learning and protective antidepressant effects in CMS model rats.

• 산업경영시스템학회지
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• 제45권4호
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• pp.53-60
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• 2022

In a group-testing method, instead of testing a sample, for example, blood individually, a batch of samples are pooled and tested simultaneously. If the pooled test is positive (or defective), each sample is tested individually. However, if negative (or good), the test is terminated at one pooled test because all samples in the batch are negative. This paper considers a queueing system with a two-stage group-testing policy. Samples arrive at the system according to a Poisson process. The system has a single server which starts a two-stage group test in a batch whenever the number of samples in the system reaches exactly a predetermined size. In the first stage, samples are pooled and tested simultaneously. If the pooled test is negative, the test is terminated. However, if positive, the samples are divided into two equally sized subgroups and each subgroup is applied to a group test in the second stage, respectively. The server performs pooled tests and individual tests sequentially. The testing time of a sample and a batch follow general distributions, respectively. In this paper, we derive the steady-state probability generating function of the system size at an arbitrary time, applying a bulk queuing model. In addition, we present queuing performance metrics such as the offered load, output rate, allowable input rate, and mean waiting time. In numerical examples with various prevalence rates, we show that the second-stage group-testing system can be more efficient than a one-stage group-testing system or an individual-testing system in terms of the allowable input rates and the waiting time. The two-stage group-testing system considered in this paper is very simple, so it is expected to be applicable in the field of COVID-19.

• 대한의생명과학회지
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• 제29권4호
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• pp.263-273
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• 2023

This study aimed to investigate effect of scalp acupuncture (SA) and repetitive transcranial magnetic stimulation (rTMS) intervention on neuromotor function in photothrombotic cerebral infarction (PCI) rat model. Sixty male SD rats were used. PCI was induced on M1 cortex of right frontal lobe. SA was performed at the Qianding (GV21), Xuanli (GB6) acupoints of ipsilesional M1. Low-frequency rTMS was delivered to contralesional M1. All rats were randomly divided into 4 groups: group A, normal (n, 15); group B, PCI without any stimulation intervention (n, 15); group C, PCI with SA (n, 15); group D, PCI with rTMS (n, 15). Rota-rod test and Ladder rung walking test (LWT) were done weekly for 8 weeks after PCI. SA or rTMS was started from post-PCI 4^th day as protocol for 8 weeks. H/E stain and IHC were done. Western blot and qRT-PCR study were performed for MAP2 and BDNF from ipsilesional M1 peri-infarction tissue. Brain MRI study was conducted to quantify the volume of cerebral infarction. As a result, left forelimb and hindlimb function significantly improved more in group C and D than control group, with expressed more BDNF and MAP2. And brain MRI showed focal infarction of right M1 after PCI, and infarction volume progressively decreased in group C and D than group B from post-PCI 5^th to 8^th week. SA or rTMS was more effective than no intervention group on neuromotor function of PCI rat model. The functional recovery was associated with stimulation intervention-related neurogenesis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.414-430
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• 2016

Verifier-local revocation (VLR) seems to be the most flexible revocation approaches for any group signature scheme, because it just only requires the verifiers to possess some up-to-date revocation information, but not the signers. Langlois et al. (PKC 2014) proposed the first VLR group signature based on lattice assumptions in the random oracle model. Their scheme has at least Õ(n²) ⋅ log N bit group public key and Õ(n) ⋅ log N bit signature, respectively. Here, n is the security parameter and N is the maximum number of group members. In this paper, we present a simpler lattice-based VLR group signature, which is more efficient by a O(log N) factor in both the group public key and the signature size. The security of our VLR group signature can be reduced to the hardness of learning with errors (LWE) and small integer solution (SIS) in the random oracle model.

• Journal of Chest Surgery
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• 제27권7호
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• pp.563-570
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• 1994

Effect of ischemic preconditioning on left ventricular function after cardiac arrest in isolated rat heart.Ischemic preconditioning reduces infarct size caused by sustained ischemia. However, the effects of preconditioning on post ischemic cardiac function are not well-known. The objective of the present study was to determine whether preconditioning would improve the recovery of left ventricular functions after cardiac arrest in isolated rat heart model.Isolated rat hearts were allowed to equilibrate for 20 minutes and were then subjected to either 5 minutes of global, normothermic transient ischemia [Group 2 and 4] or not [Group 3]. A stabilization period of perfusion lasting 5 minutes after the termination of transient ischemia was followed by a standard global, normothermic 20 minute-ischemia and 35-minute reperfusion challenge [Group 3 and 4]. These following results were odtained.1. The recovery of left ventricular developed pressures showed no significant differences between Group 3 and Group 4 at 50 [P>0.3] and 85 minute [P>0.2].2. Heart rates showed no significant differences throughout all the course of experiment and between groups [P>0.5].3. The recovery of left ventricular maximum dP/dt showed no significant differences between Group 3 and Group 4 at 50 [P>0.1] and 85 minute [P>0.2].4. The recovery of pressure-rate products showed no significant differences between Group3 and Group 4 at 50 [P>0.5] and 85 minute [P>0.1].These results suggest that ischemic preconditioning does not provide significant benefit for the postischemic left ventricular functions in isolated rat hearts.

• 동의신경정신과학회지
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• 제15권1호
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• pp.27-41
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• 2004

This study was performed to evaluate the effects of Jowiseungchungtang and fluoxetine in the chronic mild stress(CMS) model of depression in rats. Chronic exposure to mild unpredictable stress was found to depress the consumption of sucrose solution in rats for 5 weeks. These CMS-treated rats were stratified into Jowiseungchungtang group, fluoxetine group and vehicle group. And control rats were also stratified into other CMS-treated group. The change of the consumption of sucrose solution was measured, and open field test were performed to investigate the anti-depression effect of Jowiseungchungtang and fluoxetine. The results were as follows : 1. The consumption of sucrose solution was significantly reversed in Jowiseungchungtang-treated group at 7 week, but there was no significant change in other groups. 2. CMS schedule decreased body weight. Jowiseungchungtang group and fluoxetine group showed significant decrease of body weight after 6 weeks. 3. In open field test, Jowiseungchungtang group and fluoxetine group showed no significant change of exploratory activity.

• 한국시스템다이내믹스연구
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• 제7권1호
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• pp.5-26
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• 2006

Ever increasing dependence of organization on information technology stimulates interactions between individuals and groups in the process of knowledge creation, which overall impies that a reciprocal mechanism lies within the structure of the growth of group intelligence. Individual's intelligence may affect the group intelligence, and vise versa. However, the level of group intelligence is not necessarily determined by the sum of individual's intelligence but the quality of the interactions among the individuals. This study thus aims to conceptually identify the dynamic structure of interactions among the factors influencing the group intelligence level, which is believed to be used as a tool to measure the difference of intelligence between groups. To achieve this goal several attempts were made. First, determinants of intelligence at indiviual level and group level and similarities and differences between individual's and group intelligence were identified from the previous research. Second, causal loop diagrams were developed, which show how individual's intelligence influences group intelligence and vise versa. Third, it was attempted to identify and interpret which feedback loops are most influential in either improving or hapering group intelligence as a whole. Since this study remains only at exploratory level, a more detailed and workable model for field applications has to be developed in the future.

• 대한지구과학교육학회지
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• 제3권1호
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• pp.76-85
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• 2010

The purpose of this study is to examine the effect of higher grades in elementary the science process skill and scientific attitudes by multiple-intelligence. To verify research problem, the subject of this study were sixth-grade students selected from two classes of an elementary school located in U1san : the search group is composed of twenty-nine students who were participated in multiple-Intelligence situation, and the other is composed of thirty-two students(comparison group) who were participated in teacher map based learning situation. During six weeks, the multiple-Intelligence was executed in th search group while the teacher map based instruction in comparison group Post-test showed following results: First, the search group showed a significant improvement in the science process skill compared th the comparison group. Second, the search group did not showed a significant improvement in the scientific attitudes compared th the comparison group. In conclusion, multiple-Intelligence teaching model was more effective than the teacher map based teaching model on science process skill. However, since the study has a limit on an object of the study and the applied curriculum, the additional studies need to be conducted with an extended comparative group and curriculum.

• Nutritional Sciences
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• 제9권4호
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• pp.240-247
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• 2006

In this study we investigated the neuroprotective, antioxidative, and hypocholestrolemic effects of dietary soy protein and soy isoflavone in a rat focal brain ischemia model. Weaning Sprague-Dawley rats were fed a 20% casein-based diet (CA), 20% soy protein-based diet (SP), or 0.2% soy isoflavones-supplemented diet (ISO) for 6 weeks. The cortical infarction volume of the ISO group was significantly lower than that of the SP group. The thiobarbituric acid reactive substances (TBARS) were considerably lower in the ISO group than the CA group. Glutatbione peroxidase activities of the SP group were notably higher than those of the CA group. Acetylcholinesterase (AchE) activities of the SP group were significantly decreased compared to the CA group. LDL cholesterol levels and LDL/HDL ratios of the ISO group were lower than those of the CA and SP groups. Our results collectively suggest that soy isoflavones may contribute to neuroprotection by reducing the TBARS and serum LDL/HDL ratio, whereas soy protein may be associated with the regulation of cognitive functions by modulating AchE activity.