• The Korean Journal of Physiology and Pharmacology
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• v.5 no.3
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• pp.271-278
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• 2001

Oxidative stress and methylglyoxal (MG), a reactive dicarbonyl metabolites produced by enzymatic and non-enzymatic reaction of normal metabolism, induced aldose reductase (AR) expression in rat aortic smooth muscle cells (SMC). AR expression was induced in a time-dependent manner and reached at a maximum of 4.5-fold in 12 h of MG treatment. This effect of MG was completely abolished by cyclohemide and actinomycin D treatment suggesting AR was synthesized by de novo pathway. Pretreatment of the SMC with N-acetyl-L-cysteine significantly down-regulated the MG-induced AR mRNA. Furthermore, DL-Buthionine-(S,R)-sulfoximine, a reagent which depletes intracellular glutathione levels, increased the levels of MG-induced AR mRNA. These results indicated that MG induces AR mRNA by increasing the intracellular peroxide levels. Aminoguanidine, a scanvenger of dicarbonyl, significantly down-regulated the MG-induced AR mRNA. In addition, the inhibition of AR activities with statil, an AR inhibitor, enhanced the cytotoxic effect of MG on SMC under normal glucose, suggesting a protective role of AR against MG-induced cell damages. These results imply that the induction of AR by MG may contribute to an important cellular detoxification of reactive aldehyde compounds generated under oxidative stress in extrahepatic tissues.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.1-5
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• 2006

Cordyceps, one of the well-known traditional Chinese medicines, consists of the dried fungus C. sinensis growing on the larva of caterpillar. It is commonly used as a tonic of restoring vital body functions. In order to evaluate the pharmacological effects of C. militaris, the anti-oxidation and antiaging effect of cultured C. militaris growing on pupa of silkworm Bombyx mori, were investigated. The results showed! that the contents of lipofusin in myocardium were reduced and the SOD activity in the liver were elevated in a dose-dependent manner while no effect was observed for blood GSH-Px activity and liver MDA content in mice perfused with the cultured C. militaris compared to those untreated mice. Furthermore, the average life span, maximum life span and 50% death time of the fruit flies treated with cultured C. militaris were markedly prolonged. The results suggest that the cultured C. militaris growing on pupa of silkworm possesses anti-oxidation and delay senescence activity.

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.211-214
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• 2005

Objective : Post-traumatic hydrocephalus is a complication of head injury and can present with several different clinical symptoms. However, the developing factors of post-traumatic hydrocephalus and treatment are still not well known. The authors design the study to focus on incidence, causing diseases and treatment of post-traumatic hydrocephalus. Methods : The 789patients of traumatic head injury followed by admission treatment over 7days from Jan. 1997 to Dec. 2001, were divided shunt group and shunt free group. We analyzed age, sex, causing diseases, developing time of hydrocephalus and effects of shunt operation in post-traumatic hydrocephalus. Results : The incidence of post-traumatic hydrocephalus for requiring shunt was 9.2% [64cases]. Chronic hydrocephalus which developed after 14days of injury was higher incidence [51cases]. We found following variables were significantly related to shunt-dependent hydrocephalus : low GCS score at admission, initial CT finding of traumatic subarachnoid hemorrhage and intracerebral hemorrhage [including intraventricular hemorrhage]. The effect of shunt operation was not related with the spinal pressure, but had statistically significant correlation with the response of lumbar drainage. Conclusion : We conclude that development of hydrocephalus after head trauma is related to low GCS score, intracerebral hemorrhage [including intraventricular hemorrhage] and subarachnoid hemorrhage. The effect of preoperative lumbar drainage has a significant role in predicting the result of shunt operation in patient with post-traumatic hydrocephalus.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.240-244
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• 2004

A recent randomized and double-blind placebo-controlled clinical study bas indicated that Ganoderma lucidum polysaccharides (GLP) decrease blood glucose in patients with type II diabetes. The aim of this study was to investigate the effect of the GLP extract in alloxan-induced diabetic rats. Oral administration of GLP at 0.25, 0.5 and 1.0 g/kg for 4 weeks resulted in a reduction of blood glucose levels by 12.5, 18.7 and 33.7% respectively, while glibenclamide treatment brought the hyperglycemic value down to normal. The hyperglycemic effect was supported by a significant decrease in glycosylated haemoglobin and increased plasma insulin levels (p<0.01) in a dose- and time-dependent manner. This study showed that GLP has similar hypoglycemic effects as glibenclamide in alloxan-induced diabetic rats.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.7
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• pp.394-401
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• 2009

A manipulator is operated for the motion of mechanical hands or arms. When a cup including liquid inside is shifted by a manipulator, it is important to know how a free surface of the liquid moves. In this study, non dimensional parameters have been found that affect the rise of the free surface in a cup moving with constant acceleration. The non-dimensional parameters are the dimensionless time, the ratio of inertia effect to viscous effect (the Reynolds number), the aspect ratio of the liquid inside the cup and the acceleration ratio (the Froude number). Through this study, the height of the free surface rise in a cup has been predicted and the detailed velocities in the liquid have been examined. Generally, the maximum rise of the free surface is dependent on the Reynolds number and Froude number strongly, but on the aspect ratio weakly. However, the influence of the aspect ratio on the maximum rise of the free surface is not negligible in the range of 10 < Re < 100.

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.2
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• pp.106-110
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• 2017

The developmental responses of insects to temperature are important considerations in gaining a better understanding of their ecology and life histories. Temperature dependent models permit examination of the effect of temperature on the geographical distributions, population dynamics, and management of insects. The measurements of insect developmental and survival responses to temperature pose practical challenges that depend. The developmental characteristics of A. diaperinus were investigated at four temperature regimes (20, 25, 30 and $35^{\circ}C$), a relative humidity of 60%, and a light:dark photoperiod of 16:8h. The developmental time from larva to adult was 129.0, 49.8, 40.5 and 31.9 days at temperatures of 20, 25, 30 and $35^{\circ}C$, respectively. Pupal rate was 80.0%, 100%, 83.3% and 91.7% at temperatures of 20, 25, 30 and 35 respectively. There is an increasing need for a standardized manual for rearing this. Pupa had significantly lower weights at $35^{\circ}C$ than at the other temperatures. Female pupae (20mg) were significantly heavier than male (17mg).

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2939-2948
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• 2020

This paper presents an analytic solution procedure of the rotationally restrained hinged-hinged beam subjected to transverse motions at supports based on EBT (Euler-Bernoulli beam theory). The EBT solutions are compared with the solutions based on TBT (Timoshenko beam theory) for a wide range of the rotational restraint parameter (kL/EI) of slender beams whose slenderness ratio is greater than 100. The comparison shows the followings. The internal loads such as bending moment and shearing force of an extremely thin beam obtained by EBT show a good agreement with those obtained by TBT. But the discrepancy between two solutions of internal loads tends to increase as the slenderness ratio decreases. A careful examination shows that the discrepancy of the internal loads originates from their dynamic components whereas their static components show a little difference between EBT and TBT. This result suggests that TBT should be employed even for slender beams to consider the rotational effect and the shear deformation effect on dynamic components of the internal loads. The influence of the parameter on boundary conditions is examined by manipulating the spring stiffness from zero to a sufficiently large value.

• Korean Journal of Pharmacognosy
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• v.49 no.4
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• pp.298-304
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• 2018

Malus sieboldii is a dicotyledonous plant that grows widely in Jeju Island and Ganghwa Island in Korea. Malus sieboldii has been known as a detoxifying and antioxidant plant, but study on allergic diseases is not known. In this study, we investigated the effect of Malus sieboldii extract (MSE) on the activation of mast cells, which is well known to be a critical causative cell to induce allergic diseases. As a result of our experiments, MSE inhibited the degranulation and inflammatory cytokine secretion from mast cells by antigen stimulation. As the mechanism of MSE in mast cells, it inhibited the activation of Syk kinase, a essential signaling protein activated by antigen, and further inhibited activation of $PLC{\gamma}$ and MAP kinase(P38, ERK1/2, and JNK). Furthermore, in vivo animal studies showed that MSE significantly inhibited IgE-mediated passive cutaneous anaphylaxis and passive systemic anaphylaxis in a dose-dependent manner. Taken together, the results of this study showed for the first time that MSE inhibited IgE-mediated allergic responses by suppressing Syk kinase in mast cells. Therefore, it could be considered that MSE is worth developing as an anti-allergic material.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.429-438
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• 2020

The emergence of multi-drug resistant, pathogenic methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health and has created a need for novel functional therapeutic agents. In this study, we evaluated the underlying mechanisms of the anti-MRSA effect of an azaphilone pigment, sclerotiorin (SCL) from Penicillium sclerotiorum. The antimicrobial activity of SCL was evaluated using agar disc diffusion, broth microdilution, time-kill assays and biophysical studies. SCL exhibits selective activity against Gram positive bacteria including MRSA (range, MIC = 128-1028 ㎍/ml) and exhibited rapid bactericidal action against MRSA with a > 4 log reduction in colony forming units within three hours of administration. Biophysical studies, using fluorescent probes and laser or electron microscopy, demonstrated a SCL dose-dependent alternation in membrane potential (62.6 ± 5.0.4% inhibition) and integrity (> 95 ± 2.3%), and the release of UV260 absorbing materials within 60 min (up to 3.2 fold increase, p < 0.01) of exposure. Further, SCL localized to the cytoplasm and hydrolyzed plasmid DNA. While in vitro checkerboard studies revealed that SCL potentiated the antimicrobial activity of topical antimicrobials such as polymixin, neomycin, and bacitracin (Fractional Inhibitory Concentration Index range, 0.26-0.37). Taken together these results suggest that SCL targets the membrane and DNA of MRSA to facilitate its anti-MRSA antimicrobial effect.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.4
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• pp.297-305
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• 2021

Luteolin, a sort of flavonoid, has been reported to be involved in neuroprotective function via suppression of neuroinflammation. In this study, we investigated the protective effect of luteolin against oxidative stress-induced cellular senescence and its molecular mechanism using hydrogen peroxide (H₂O₂)-induced cellular senescence model in House Ear Institute-Organ of Corti 1 cells (HEI-OC1). Our results showed that luteolin attenuated senescent phenotypes including alterations of morphology, cell proliferation, senescence-associated 𝛽-galactosidase expression, DNA damage, as well as related molecules expression such as p53 and p21 in the oxidant challenged model. Interestingly, we found that luteolin induces expression of sirtuin 1 in dose- and time-dependent manners and it has protective role against H₂O₂-induced cellular senescence by upregulation of sirtuin 1 (SIRT1). In contrast, the inhibitory effect of luteolin on cellular senescence under oxidative stress was abolished by silencing of SIRT1. This study indicates that luteolin effectively protects against oxidative stress-induced cellular senescence through p53 and SIRT1. These results suggest that luteolin possesses therapeutic potentials against age-related hearing loss that are induced by oxidative stress.