• Plant Biotechnology Reports
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• v.3 no.3
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• pp.183-190
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• 2009

Rho-related GTPase of plants (ROP) plays an important role in plant growth and development as a signaling protein. Plant RopGEFs are recently identified ROP activator proteins in Arabidopsis. In this study, we cloned 14 RopGEFs in Arabidopsis and characterized their expression patterns in response to abiotic stresses. Fourteen RopGEF genes were categorized into three groups based on their amino acid homologies and molecular sizes. Most RopGEFs were expressed predominantly in flower but some RopGEFs displayed a tissue-specific expression pattern. RopGEF1, 4, 5, and 11 were expressed in all tissues including root and leaves whereas RopGEF7, 8, 9, and 13 were expressed only in flowers. The transcript levels of 14 RopGEFs were changed significantly depending upon abiotic stresses such as cold, heat, drought and salts. RopGEF5 transcription was up-regulated by salt and drought treatment but down-regulated by heat. RopGEF14 transcript level was also increased by salt but decreased by heat stress. The transcript levels of RopGEF1, 7, 9, and 12 were enhanced in response to heat stress but showed no changes in response to cold stresses. Drought stress activated Group 3 RopGEFs such as RopGEF5 and 7. Taken together, 14 RopGEFs are responding to the abiotic stresses individually or as a group.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.22-27
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• 2009

Retinopathy of prematurity (ROP) is a major cause of blindness that affects premature infants. With advances in neonatology, ROP is likely to emerge as the most serious problem of vision loss in children even in developed countries; such a situation could be called the third epidemic of ROP. However, controversy and uncertainty still surround favorable outcomes of ROP. For successfully controlling ROP, timely and accurate screening is crucial because early treatment leads to favorable outcomes. Standard guidelines, including ROP classification, have provided satisfactory instructions for the screening and treatment of ROP. To improve the structural and functional outcomes of ROP, optimizing the timing of surgical interventions including cryotherapy, laser-photocoagulation, encircling, and vitrectomy is essential; these interventions can prevent the sequelae of ROP. It is essential for the neonatologist and the ophthalmologist to cooperate extensively for the successful treatment of ROP.

• Clinical and Experimental Pediatrics
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• v.65 no.3
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• pp.115-126
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• 2022

Retinopathy of prematurity (ROP) is among the most common causes of childhood blindness. Three phases of ROP epidemics have been observed worldwide since ROP was first described in the 1940s. Despite advances in neonatal care, the occurrence of ROP and associated visual impairment has been increasing somewhere on Earth and remains difficult to control. Conventional treatment options for preventing ROP progression include retinal ablation using cryotherapy or laser therapy. With the emergence of anti-vascular endothelial growth factor (anti-VEGF) treatment for ocular diseases, the efficacy and safety of anti-VEGF therapy for ROP have recently been actively discussed. In the advanced stage of ROP with retinal detachment, surgical treatment including scleral buckling or vitrectomy is needed to maintain or induce retinal attachment. At this stage, the visual outcome is usually poor despite successful anatomical retinal attachment. Therefore, preventing ROP progression by timely screening examinations and treatment remains the most important part of ROP management.

• Journal of Internet Computing and Services
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• v.19 no.3
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• pp.15-23
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• 2018

A code reuse attack is an attack technique that can execute arbitrary code without injecting code directly into the stack by combining executable code fragments existing in program memory and executing them continuously. ROP(Return-Oriented Programming) attack is typical type of code reuse attack and serveral defense techniques have been proposed to deal with this. However, since existing methods use Rule-based method to detect attacks based on specific rules, there is a limitation that ROP attacks that do not correspond to previously defined rules can not be detected. In this paper, we introduce a method to detect ROP attack by learning command pattern used in ROP attack code using RNN(Recurrent Neural Network). We also show that the proposed method effectively detects ROP attacks by measuring False Positive Ratio, False Negative Ratio, and Accuracy for normal code and ROP attack code discrimination.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.5
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• pp.217-222
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• 2013

Return-Oriented Programming(ROP) is an advanced code-reuse attack like a return-to-libc attack. ROP attacks combine gadgets in program code area and make functions like a Turing-complete language. Some of previous defense methods against ROP attacks show high performance overhead because of dynamic execution flow analysis and can defend against only certain types of ROP attacks. In this paper, we propose Indirect Branch Target Address Verification (IBTAV). IBTAV detects ROP attacks by checking if target addresses of indirect branches are valid. IBTAV can defends against almost all ROP attacks because it verifies a target address of every indirect branch instruction. Since IBTAV does not require dynamic execution flow analysis, the performance overhead of IBTAV is relatively low. Our evaluation of IBTAV on SPEC CPU 2006 shows less than 15% performance overhead.

• Clinical and Experimental Pediatrics
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• v.58 no.2
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• pp.52-59
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• 2015

Purpose: This study aimed to investigate the relative weight gain at 2-week intervals up to 6 weeks after birth to predict retinopathy of prematurity (ROP) requiring treatment among very low birth weight infants. Methods: A total of 211 preterm infants with birth weights <1,500 g and gestational age <32 weeks were retrospectively reviewed. The main outcome was the development of ROP requiring treatment. Body weight measurements were recorded daily. Relative weight gains (g/kg/day) were calculated at the second, fourth, and sixth week after birth. Results: Of the 211 infants, 89 developed ROP, of which 41 spontaneously regressed and 48 with early treatment of ROP type I required laser treatment. The relative weight gain at 2, 4, and 6 weeks postnatal age was significantly lower in infants with ROP requiring treatment than in infants without ROP or those with spontaneous regression (P<0.001, P=0.005, and P=0.004, respectively). On logistic regression, poor relative weight gain in the first 2 weeks was found to be related to ROP requiring treatment (adjusted odds ratio, 0.809; 95% confidence interval, 0.695-0.941; P=0.006). Relative weight gain at 2 weeks postnatal age was significantly lower in infants with ROP requiring treatment compared to that in ROP requiring no treatment (P=0.012). Conclusion: Poor postnatal weight gain in the first 2 weeks of life is an important and independent risk factor for ROP requiring treatment. Postnatal weight gain can predict the development of severe ROP requiring treatment.

• Parasites, Hosts and Diseases
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• v.56 no.5
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• pp.429-435
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• 2018

Toxoplasma gondii is a ubiquitous protozoan parasite responsible for causing toxoplasmosis. Preventive measures for toxoplasmosis are currently lacking and as such, development of novel vaccines are of urgent need. In this study, we generated 2 virus-like particles (VLPs) vaccines expressing T. gondii rhoptry protein 4 (ROP4) or rhoptry protein 18 (ROP18) using influenza matrix protein (M1) as a core protein. Mice were intranasally immunized with VLPs vaccines and after the last immunization, mice were challenged with ME49 cysts. Protective efficacy was assessed and compared by determining serum antibody responses, body weight changes and the reduction of cyst counts in the brain. ROP18 VLPs-immunized mice induced greater levels of IgG and IgA antibody responses than those immunized with ROP4 VLPs. ROP18 VLPs immunization significantly reduced body weight loss and the number of brain cysts in mice compared to ROP4 VLPs post-challenge. These results indicate that T. gondii ROP18 VLPs elicited better protective efficacy than ROP4 VLPs, providing important insight into vaccine design strategy.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1064-1067
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• 2012

Return-Oriented Programming(ROP) 공격은 버퍼 오버플로우 공격, Return-into libc 공격의 계보를 이어 소프트웨어의 취약점을 공격하는 대표적인 기술 중 하나이다. 이 공격은 윈도우 운영체제 상에서의 Exploitation, iOS DEP 우회 및 코드 사이닝과 같은 기술을 무력화하기 위해 사용되고 있는 취약점 공격법이다. 그렇기 때문에 ROP 공격이 소개된 이후부터 현재까지 탐지법 및 방어법에 대한 논의가 활발하게 이루어지고 있다. 본 논문에서는 이러한 ROP 공격을 막기 위한 방법들을 특징에 따라 세 가지 종류로 분류하여 소개하고, 각각의 방법들의 장점과 단점을 비교 분석하여 향후 ROP 방어에 관한 연구에 기여를 하고자 한다.

• Structural Engineering and Mechanics
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• v.68 no.1
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• pp.95-101
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• 2018

The low rate of penetration and short lifetime of drilling bit served as the most common problems encountered in hard formation drilling, thus leading to severe restriction of drilling efficiency in oil and gas reservoir. This study developed a new local impact drilling method to enhance hard formation drilling efficiency. The limitation length formulas of radial/lateral cracks under static indentation and dynamic impact are derived based on the experimental research of Marshall D.B considering the mud column pressure and confining pressure. The local impact rock breaking simulation model is conducted to investigate its ROP raising effect. The results demonstrate that the length of radial/lateral cracks will increase as the decrease of mud pressure and confining pressure, and the local impact can result in a damage zone round the impact crater which helps the rock cutting, thus leading to the ROP increase. The numerical results also demonstrate the advantages of local impact method for raising ROP and the vibration reduction of bit in hard formation drilling. This study has shown that the local impact method can help raising the ROP and vibration reduction of bit, and it may be applied in drilling engineering.

• Parasites, Hosts and Diseases
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• v.44 no.3
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• pp.251-254
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• 2006

Monoclonal antibody (mAb) Tg786 against Toxoplasma gondii has been found to detect a 42-kDa rhoptry protein (ROP6) which showed protease activity and host cell binding characteristics after secretion. Using the mAb, a colony containing a 3'-UTR was probed in a T. gondii cDNA expression library. A full length cDNA sequence of the rhoptry protein was completed after 5'-RACE, which consisted of 1,908 bp with a 1,443 bp ORF. The deduced amino acid sequence of ROP6 consisted of a polypeptide of 480 amino acids without significant homology to any other known proteins. This sequence contains an amino terminal stop transfer sequence downstream of a short neutral sequence, hydrophilic middle sequence, and hydrophobic carboxy terminus. It is suggested that the ROP6 is inserted into the rhoptry membrane with both N- and C-termini.