• Smart Structures and Systems
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• 제10권3호
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• pp.229-251
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• 2012

Guided waves have shown a great potential for structural health monitoring (SHM) applications. In contrast to traditional non-destructive testing (NDT) methodologies, a key element of SHM approaches is the high process of automation. The monitoring system should decide autonomously whether the host structure is intact or not. A basic requirement for the realization of such a system is that the sensors are permanently installed on the host structure. Thus, baseline measurements become available that can be used for diagnostic purposes, i.e., damage detection, localization, etc. This paper contributes to guided wave-based inspection in anisotropic materials for SHM purposes. Therefore, computational strategies are described for both, the solution of the complex equations for wave propagation analysis in composite materials based on exact elasticity theory and the popular global matrix method, as well as the underlying equations of two active damage localization algorithms for anisotropic structures. The result of the global matrix method is an angular and frequency dependent wave velocity characteristic that is used subsequently in the localization procedures. Numerical simulations and experimental investigations through time-delay measurements are carried out in order to validate the proposed theoretical model. An exemplary case study including the calculation of dispersion curves and damage localization is conducted on an exemplary unidirectional composite structure where the ultrasonic signals processed in the localization step are simulated with the spectral element method. The proposed study demonstrates the capabilities of the proposed algorithms for accurate damage localization in anisotropic structures.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3409-3416
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• 2012

Aim: It is well known that polycyclic aromatic hydrocarbons (PAHs) such as benzo (a) pyrene have carcinogenic properties and may cause many types of cancers in human populations. Genetic susceptibility might be due to variation in genes encoding for carcinogen metabolizing enzymes, such as cytochrome P-450 (CYP450). Our study aimed to investigate the effect of genetic polymorphisms of CYP1A1 (m1 and m2) on genetic damage in 115 coal-tar workers exposed to PAHs at their work place. Methods: Genetic polymorphisms of CYP1A1 were determined by the PCR-RFLP method. Comet and buccal micronucleus assays were used to evaluate genetic damage among 115 coal tar workers and 105 control subjects. Results: Both CYP1A1 m1 and CYP1A1 m2 heterozygous and homozygous (wt/mt+mt/mt) variants individually as well as synergistically showed significant association (P<0.05) with genetic damage as measured by tail moment (TM) and buccal micronuclei (BMN) frequencies in control and exposed subjects. Conclusion: In our study we found significant association of CYP1A1 m1 and m2 heterozygous (wt/mt)+homozygous (mt/mt) variants with genetic damage suggesting that these polymorphisms may modulate the effects of PAH exposure in occupational settings.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2002년도 추계국제학술대회
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• pp.169-169
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• 2002

The mobilizable amount of transition metals is a fraction of the total amount of the metal from urban particulate matter. Although the fraction is small, some metals (Fe, Cu) are the major participants in a reaction that generates reactive oxygen species (ROS), which can damage various biomolecules. Damaging effects of the metals can be measured by the single strand breakage (SSB) of X174 RFI DNA or the carbonyl formation of protein. In another study, we have shown that more metals are mobilized by PM2.5 than by PM10 in general. DNA SSB of >20% for PM2.5 and >15% for PM10 was observed in the presence of chelator (EDTA or citrate)/reductant (ascorbate), compared to the control (<3%) only with the chelator. The carbonyl formation by both PMs was very similar in the presence of the chelator, regardless of the kind of proteins. Compared to the control in the absence of chelator/reductant, 3.3 times and 4.9 times more carbonyl formation for PM2.5 and PM10, respectively, was obtained with BSA in the presence of chelator/reductant, showing that PM10 induced 33% more damage than PM2.5. However, 4.8 times and 1.9 times more carbonyl formation for PM2.5 and PM10, respectively, was observed with lysozyme in the presence of chelator/reductant, showing that PM2.5 induced 250% more damage than PM10. Although different proteins showed different sensitivities toward ROS, all these results indicate that the degrees of the oxidation of or damage to the biomolecules by the mobilized metals were higher with PM2.5 than with PM10. Therefore, it is expected that more metals mobilized from PM2.5 than from PM10, more damage to the biomolecules by PM2.5 than by PM10. We suggest that when the toxicity of the dust particle is considered, the particle size as well as the mobilizable fraction of the metal should be considered in place of the total amounts.

• Journal of Animal Science and Technology
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• 제63권5호
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• pp.984-997
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• 2021

This study sought to evaluate DNA damage and repair in porcine postovulatory aged oocytes. The DNA damage response, which was assessed by H2A.X expression, increased in porcine aged oocytes over time. However, the aged oocytes exhibited a significant decrease in the expression of RAD51, which reflects the DNA damage repair capacity. Further experiments suggested that the DNA repair ability was suppressed by the downregulation of genes involved in the homologous recombination (HR) and nonhomologous end-joining (NHEJ) pathways. The expression levels of the cell cycle checkpoint genes, CHEK1 and CHEK2, were upregulated in porcine aged oocytes in response to induced DNA damage. Immunofluorescence results revealed that the expression level of H3K79me2 was significantly lower in porcine aged oocytes than in control oocytes. In addition, embryo quality was significantly reduced in aged oocytes, as assessed by measuring the cell proliferation capacity. Our results provide evidence that DNA damage is increased and the DNA repair ability is suppressed in porcine aged oocytes. These findings increase our understanding of the events that occur during postovulatory oocyte aging.

• Steel and Composite Structures
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• 제30권4호
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• pp.351-364
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• 2019

Earthquake and fire are both severe disasters for building structures. Since earthquake-induced damage will weaken the structure and reduce its fire endurance, it is important to investigate the behavior of structure subjected to post-earthquake fire. In this paper, steel-concrete composite beam-to-column joints were tested under fire with pre-damage caused by cyclic loads. Beforehand, three control specimens with no pre-damage were tested to capture the static, cyclic and fire-resistant performance of intact joints. Experimental data including strain, deflection and temperature recorded at several points are presented and analyzed to quantify the influence of cyclic damage on fire resistance. It is indicated that the fire endurance of damaged joints decreased with the increase of damage level, mainly due to faster heating-up rate after cyclic damage. However, cracks induced by cyclic loading in concrete are found to mitigate the concrete spalling at elevated temperatures. Moreover, the relationship between fire resistance and damage degree is revealed from experimental results, which can be applied in fire safety design and is worthwhile for further research.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권2호
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• pp.189-195
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• 2010

Excessive oral and maxillofacial bleeding causes upper airway obstruction, bronchotracheal & gastric aspiration and hypovolemic shock. Therefore, the rapid & correct bleeding control is very important for life-saving in the medical emergency room. In spite of the bleeding control methods of the wound suture & direct pressure, the postoperative bleeding can be occurred, because of the presence of various bleeding disorders & postoperative delayed wound infections. The proper care of bleeding disorders & wound infections are very important for the control of the delayed postoperative rebleeding. In spite of these methods, active oral bleeding can be presented by the other causes of head injury. A rare but particularly dangerous sort of bleeding that may have an especial importance to the patient with severe basal skull fracture that damage large vessels and even the cavernous sinus. The occurrence of profuse nasal or oropharyngeal bleeding may arise from damage to the anterior and posterior ethmoidal vessels, but when mixed with brain tissue it is evidence of mortal damage. In this condition, rapid entire oropharyngeal packing is essential for the control of active oral bleeding. This is a case report of rapid rational bleeding control method by much amount of wet gauze packings, in a 44-years-old male patient with active oropharyngeal bleeding by basal skull fractures.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권2호
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• pp.83-91
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• 2002

The protection of silkworm and its host plants from various kinds of pests parasite and predator is a chronic problem in sericulture. Silkworms and its primary food plants are heavily damaged by large number of pest. The major pests of primary tasar food plants (Terminalia arjuna and Terminalia tomentosa) are the gall insect (Trioza fletcheri minor). Various species of aphids (Eutrichosiphum sp.) have been recorded to damage oak tasar food plants whereas muga silkworm host plants (Machilus bombycina and Litsaea polyantha) are generally attacked by stem bores (Zeuzera multistrigata). Castor (Ricinus communis) is one of the primary host plant of eri silkworm and extensive damage is caused by the castor white fly (Trialeurodes ricini). Insects pests are major enemies of silkworms. Parasites (Blepharipa zebina, Exorista bombycis, Apateles glomeratus), predators (Canthecona furcellata, Sycanus collaris, Hierodulla bipapilla), wasps (Vespa orientalix) and ants (Oecophylla smargdina) continues to cause damage to silk industry. It is estimated that the losses due to parasites and predators are to an extent of 15-20 percent and varies from crop to crop. The complexities in the behaviour and life cycle of pest population existing in semi ecosystem warrant a special attention for their effective management specially in changing scenario for our modern sericulture. Though use of synthetic insecticides has provided us with effective control of almost all major pests and predators, yet their undesirable side effects limit their continued use. Biological control is one of the most important method which can be used to control the pests, parasites and predators population in sericulture. Various potential parasitoids, which can be utilized as an agent of biological control in sericulture have been screened. The natural enemies of the uzi fly (E. bombycis and B. zebina ) are already present in the nature. Nesolynx thymus, Trichria sp., Splangia endius, Dirhinus sp., Trichopria sp., Trichomalopsis apanteloctena and Pediobius sp. are the major parasitoids effective against uzi fly pupa. The scelionid Psix striaticeps and Trissolcus sp. are the Potential egg Parasitoids against stink bug (Canthecona furcellata). Various other native natural potential parasitoids have been screened and suitable strategies have been developed to check the population of pest insect in sericulture.

• 한국수자원학회논문집
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• 제39권1호
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• pp.1-9
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• 2006

최근 이상홍수로 인한 인명과 재산피해가 급격히 증가하여 홍수피해를 경감시키기 위한 치수사업의 필요성은 인식하고 있으나, 사업타당성을 정확하고 객관적으로 분석할 수 있는 경제성분석 방법이 미진한 실정이다. 본 연구는 기존의 치수경제성분석을 개선하기 위한 것으로 현행 국내에서 사용중인 치수경제성분석의 문제점을 파악하고 외국의 사례와 비교 분석하여 개선방향을 도출하고 이를 바탕으로 다차원 홍수피해산정방법(MD-FDA Multi-Dimensional Flood damage analysis)을 개발하였다 주된 내용은 예상피해지역의 자산조사를 통하여 $100\%$피해규모를 산정하고, 침수심 조건에 따라 피해율을 적용하여 예상 홍수피해액을 계산하는 것이다. 여기에서, GIS와 연계하여 침수면적뿐만 아니라 침수심의 공간적 분포를 고려하여 피해액을 보다 정확하게 산정할 수 없다. 본 연구에서 개발한 다차원 흥수피해산정방법은 기존 방법에서 야기되었던 문제점을 개선하고 계속해서 업데이트되는 국가통계자료를 이용함으로써 보다 합리적이고 정확한 피해액을 산정할 수 있으리라 사료된다.

• BMB Reports
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• 제48권6호
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• pp.354-359
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• 2015

Vascular smooth muscle cells (VSMCs) undergo death during atherosclerosis, a widespread cardiovascular disease. Recent studies suggest that oxidative damage occurs in VSMCs and induces atherosclerosis. Here, we analyzed oxidative damage repair in VSMCs and found that VSMCs are hypersensitive to oxidative damage. Further analysis showed that oxidative damage repair in VSMCs is suppressed by a low level of poly (ADP-ribosyl)ation (PARylation), a key post-translational modification in oxidative damage repair. The low level of PARylation is not caused by the lack of PARP-1, the major poly(ADP-ribose) polymerase activated by oxidative damage. Instead, the expression of poly(ADP-ribose) glycohydrolase, PARG, the enzyme hydrolyzing poly(ADP-ribose), is significantly higher in VSMCs than that in the control cells. Using PARG inhibitor to suppress PARG activity facilitates oxidative damage-induced PARylation as well as DNA damage repair. Thus, our study demonstrates a novel molecular mechanism for oxidative damage-induced VSMCs death. This study also identifies the use of PARG inhibitors as a potential treatment for atherosclerosis. [BMB Reports 2015; 48(6): 354-359]

• 한국응용곤충학회지
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• 제18권2호
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• pp.101-106
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• 1979

대두의 주요해충인 콩나방의 피해를 경감시키기 위해 생물학적구제책을 모색하기 위해서 재래수집종에 콩나방피해율과 형태적특성과의 관계를 검토하였다. 또 품종및 경종조건을 달리한 후 콩나방의 피해를 조사한 결과는 다음과 같다. 1474계통에 대한 콩나방피해율은 최고$38\%$에서 전혀 피해가 없는 계통까지 분포하고 평균피해율은 $5.2\%$이였다. 형태적특성으로서 협의 모용밀도 및 색과 콩나방의 피해율과는 일정한 상관성이 없으나 콩나방피해율과 maturity group 또는 진딧물피해와는 공히 $5\%$ 수준에서 정의 상관관계가 있었고 maturity group V에서 가장피해율이 높았으며 일반잎피해정도와 콩나방피해와는 부의 상관관계가 있었다. 특이한 것은 청색의 종피색을 띤 계통들에서 콩나방피해가 현저히 늘은 점이다. 파종기별 콩나방의 피해정도는 6월20일 파종구가 제일 심하여 만파구가 피해율이 현저히 높은데 이들 피해정도는 착협시기뿐만 아니라 착협에서 성숙기까지의 기간에도 관계가 있는것으로 보여진다. 재식거라에 따른 중나방피해는 소식할수록 큰 편이고 6개품종중 봉의, 충북백이 저항성인 반면 clark, 금강대립이 이충성품종으로 나타났다.