• 한국지하수토양환경학회지:지하수토양환경
• /
• 제27권3호
• /
• pp.22-40
• /
• 2022

The goal of this study was to estimate the possible scattering distance of deicer from the highway and the impact range of deicer on soil quality in terms of plant growth. Among the major elements (Ca²⁺, Cl^- and Na⁺) of deicer, Ca²⁺and Cl^- are usually applied as fertilizer to soil. Therefore both elements (Ca²⁺and Cl^-) were not appropriate for a tracer of deicer at the agricultural area. In this study, SAR (sodium adsorption ratio) of soil was proposed as an alternative tracer to confirm the distribution of the deicer around the highway areas. Because deicer is the main anthropogenic source of Na⁺ around the highway areas and does harm to the physical properties of soil and plant growth through the destruction of soil aggregate, SAR would be an recommendable tracer to access the distribution of deicer as well as adverse effect on soil quality at highway areas. The influence range of deicer based on SAR of soil was estimated to be less than 20 m distance from the highway even though the possible flying distance of deicer was found to be more than 100 m from the highway. However the deicer seriously deposited within 10 m from the highway.

• 한국대기환경학회지
• /
• 제2권3호
• /
• pp.1-10
• /
• 1986

Nowadays, air pollution by increasing consumption of fossil fuels resulting from rapidly growing population and industrialization has caused the adverse effects on terrestrial ecosystems and become one of the most serious problems causing environmental discriptions. Air pollution such as $SO_2, HF, NO_X,$ fly ash, ozone and PAN might influence plant growth, reproduction, nutrient cycling, photosynthesis and predisposition to entomological and pathological stresses on plants. Furthermore, accumulation of those toxic substances in forests might cause subtle or serious changes in the structure and function of forest ecosystems. Since 1970s, a number of large industrial complexes had been constructed as a part of industrialization plan in Korea. Accordingly, the forest exosystems around them has been under chronic influences of air pollution and effects of air pollution on plants became a matter of concern. In Yocheon Industrial Complex which consisted of lots of petrochemical plants and a phosphatic fertilizer manufacturing plant, forests has been exposed to chronic air pollution, mainly HF and $SO_2$ gas, Various reports were available to investigate the potential effects of air pollution on crops and forest trees in Yocheon. Kim and Kim surveyed vegetation by naked eye method and reported 71 families, 150 genera and 158 species were growing within a 2 km from air pollution sources in 1981. Needle injuries on Pinus spp. in the polluted area water reported by Kim, et al. and Kim, et al. Kim, et al. investigated the primary production of Pinus thunbergii forests in the polluted area and verified that growth inhibition of Pinus thunbergii was attributable to air pollution. Thus, previous reports suggested that forest ecosystems around Yocheon Industrial Complex were influenced adversely by air pollution. The objective of this study was to investigate the subtle ecological changes in forest community exposed to chronic air pollution in Yocheon.

• 한국지반공학회논문집
• /
• 제39권11호
• /
• pp.23-31
• /
• 2023

콘크리트 궤도의 침하는 고속열차의 안전한 운행을 크게 저해할 수 있으며 복구에 상당한 비용이 소요되므로 최근 큰 문제로 대두되고 있다. 침하의 가장 큰 원인 중 하나는 터널공사의 부산물로 발생하는 암석재료를 적정한 입도분를 가진 토사 혼합 없이 하부노반 성토에 사용하기 때문으로 보고되고 있다. 본 논문에서는 암석재료로 성토된 하부노반의 부분 보강으로 인한 침하억제 효과를 수치해석으로 평가하였다. 하부노반에 일정하게 배치된 기둥 형태의 보강 영역은 상부노반에 지반아칭을 유발하게 되며 성토하중이 보강된 영역에 집중하게 되어 침하가 억제되는 효과가 있다. 유한요소해석을 통하여 보강된 영역의 크기, 강성, 간격이 하부노반의 침하억제에 미치는 효과를 평가하였으며, 해석 결과를 토대로 침하를 허용치 이내로 억제하기 위한 최소 보강 간격을 결정하는 설계 방법을 제안하였다.

• 치위생과학회지
• /
• 제23권4호
• /
• pp.264-270
• /
• 2023

Background: Resin-based dental materials release residual monomers or other substances from incomplete polymerization into the oral cavity, thereby causing adverse biological effects on oral tissue. 10-Methacryloyloxydecyl dihydrogen phosphate (10-MDP), an acidic monomer containing dihydrogen phosphate and methacrylate groups, is the most commonly used component of resin-based dental materials, such as restorative composite resins, dentin adhesives, and resin cements. Although previous studies have reported the cytotoxicity and biocompatibility in various cultured cells, the effects of resin monomers on cellular aging have not been reported to date. Therefore, this study aimed to investigate the effects of the resin monomer 10-MDP on cellular senescence and inflamm-aging in vitro. Methods: After stimulation with 10-MDP, MC3T3-E1 osteoblast-like cells were examined for cell viability by WST-8 assay and reactive oxygen species (ROS) production by flow cytometry. The protein and mRNA levels of molecular markers of aging were determined by western blotting and RT-PCR analysis, respectively. Results: Treatment with 0.05 to 1 mM 10-MDP for 24 hours reduced the survival of MC3T3-E1 cells in a concentration-dependent manner. The intracellular ROS levels in the 10-MDP-treated experimental group were significantly higher than those in the control group. 10-MDP at a concentration of 0.1 mM increased p53, p16, and p21 protein levels. Additionally, an aging pattern was observed with blue staining due to intracellular senescence-associated beta-galactosidase activity. Treatment with 10-MDP increased the levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-8, however their expression was decreased by mitogen-activated-protein-kinase (MAPK) inhibitors. Conclusion: Taken together, these results suggest that the exposure of osteoblast-like cells to the dental resin monomer 10-MDP, increases the level of cellular senescence and the inflammatory response is mediated by the MAPK pathway.

• 한국전자통신학회논문지
• /
• 제18권6호
• /
• pp.1023-1030
• /
• 2023

본 논문은 눈, 비, 안개 등 열악한 운용환경에도 강건한 표적검출 특성을 가지는 FMCW LiDAR에 대해서 기술하고 있다. 특히 FMCW LiDAR의 거리 해상도, 가간섭거리 및 최대측정거리 성능에 직접적으로 영향을 미치는 주파수변조레이저의 성능개선에 대해 기술하고 있다. 불평형 Mach-Zehnder 레이저간섭계를 활용하여, 레이저의 발진주파수의 변화율을 실시간 측정하고, 주파수변조 오차를 보정하는 광학식 위상동기루프 기술을 이용한 주파수변조 방법에 대해 기술하였다. 가간섭거리가 긴 레이저 광원을 발진하기 위해 확장공진기형 레이저다이오드를 적용하였으며, 레이저에서 발진되는 주파수 측정을 위해 광집적회로 구조의 레이저간섭계를 적용하였다. 개발된 FMCW LiDAR의 대역폭과 거리해상도는 각각 10.045GHz와 0.84mm로 측정되었다.

• 한국방재안전학회논문집
• /
• 제16권4호
• /
• pp.109-121
• /
• 2023

수제는 하천 내에서 다양한 생태환경을 제공할 수 있어 하천의 환경 기능을 향상시키는 데 활용될 수 있다. 그러나 수제로 인해 변화하는 흐름이 환경 기능을 향상시키는 것만은 아니며, 부정적인 영향을 초래할 수 있다. 따라서 본 연구에서는 수리실험을 통해 수제의 설치로 인한 흐름변화를 분석하여, 어류서식처에 미치는 영향을 검토하였다. 어류의 서식환경의 주요 인자로는 유속, 난류운동에너지 및 재순환영역 등이 있으며, 그 중 난류운동에너지와 재순환영역을 중점적으로 검토하였다. 수제의 간격과 잠김정도를 실험조건으로 설정하여 총 8가지 케이스에서의 실험을 수행하였으며, 실험결과 수제의 간격이 짧고, 잠김정도가 낮을수록 난류운동에너지와 재순환영역의 크기가 증가하여 어류서식처에 미치는 영향이 크게 나타났다.

• Safety and Health at Work
• /
• 제14권4호
• /
• pp.384-389
• /
• 2023

Background: Exposure to welding fume is associated with adverse effects on worker health. The use of various control measures can reduce levels of exposure and the resulting health effects. However, little is known about the factors that may influence workers' use of control measures in the workplace and their perceived intervention needs. This study aimed to investigate workers' and other stakeholders' views on ways to improve the use of welding fume control measures in Australian workplaces. Methods: We conducted a series of online focus group discussions and individual interviews with participants who have some occupational involvement in welding, whether as workers, employers or industry representatives, union representatives, or regulators. A semi-structured question guide was used, and all discussions and interviews were recorded and transcribed for analysis. Results: Five focus group discussions and five individual interviews were conducted with a total of 21 participants. Three major themes emerged. The first addressed the current awareness of welding fume harms and concern about exposure; the second focussed on the current use of control measures, and barriers and facilitators to their use; and the last centred around intervention needs and the contents of a potential effective intervention. Conclusion: Improving the use of control measures to prevent exposure to welding fume requires knowledge around the barriers and facilitators of control, use, and the intervention needs of stakeholders. This study has provided such knowledge, which will facilitate the design and implementation of an intervention to reduce welding fume exposure and ultimately protect the health of workers.

• 중환자간호학회지
• /
• 제17권1호
• /
• pp.30-43
• /
• 2024

Purpose : Post-intensive care syndrome (PICS) is characterized by a constellation of mental health, physical, and cognitive impairments, and is recognized as a long-term sequela among survivors of intensive care units (ICUs). The objective of this study was to explore the impact of intensive care experience (ICE) on the development of PICS in individuals surviving critical care. Methods : This secondary analysis utilized data derived from a prospective, multicenter cohort study of ICU survivors. The cohort comprised 143 survivors who were enrolled between July and August 2019. The original study's participants completed the Korean version of the ICE questionnaire (K-ICEQ) within one week following discharge from the ICU. Of these, 82 individuals completed the PICS questionnaire (PICSQ) three months subsequent to discharge from hospital. The influence of ICE on the manifestation of PICS was examined through Partial Least Squares-Structural Equation Modeling (PLS-SEM). Result : The R² values of the final model ranged from 0.35 to 0.51, while the Q² values were all greater than 0, indicating adequacy for prediction of PICS. Notable pathways in the relationship between the four ICE dimensions and the three PICS domains included significant associations from 'ICE-awareness of surroundings' to 'PICS-cognitive', from 'ICE-recall of experience' to 'PICS-cognitive', and from 'ICE-frightening experiences' to 'PICS-mental health'. Analysis found no significant moderating effects of age or disease severity on these relationships. Additionally, gender differences were identified in the significant pathways within the model. Conclusion : Adverse ICU experiences may detrimentally impact the cognitive and mental health domains of PICS following discharge. In order to improve long-term outcomes of individuals who survive critical care, it is imperative to develop nursing interventions aimed at enhancing the ICU experience for patients.

• 한국해양환경ㆍ에너지학회지
• /
• 제9권4호
• /
• pp.243-252
• /
• 2006

산업혁명이후 대기중 이산화탄소 등 온실기체의 농도는 꾸준히 증가하고 있고, 이에 따른 기후변화와 해수면 상승 등의 문제의 심각성에 대한 전세계적인 관심이 증가하고 있다. 따라서 인간활동에 의해 대기중으로 방출되는 $CO_2$의 배출량을 줄이기 위한 다양한 방법이 제안되고 있다. 그 중에서 최근 $CO_2$를 해양 심층부에 직접 투기하거나(해양분사법), 해저면(해양저류법)또는 지중에 주입(해양지중법)하여 격리하고자 하는 방안에 대한 국내외 관심이 높아지고 있다. 특히 해양은 대기와는 비교도 할 수 없을 만큼 큰 $CO_2$의 저장고로서 이미 대기중 $CO_2$ 농도의 증가는 표층해수로 유입되는 $CO_2$ 유입량을 증가시키고 있다. 향후 100년간 해수로 유입되는 $CO_2$는 크게 증가할 것으로 예상되는데 이에 따라 표층 해수의 pH는 최대 0.4이상 낮아질 수 있다는 전망이 나오고 있다. 이와 같은 해수의 산성화는 산호, 석회조류(cocolithophorid)와 같이 몸의 일부를 석회질로 구성하는 생물들의 성장에 심각한 저해 영향을 미칠 수 있음이 실험적으로 밝혀지고 있다. 뿐만 아니라 성게나 어류의 유생과 같이 환경변화에 민감한 생물들은 $0.1{\sim}0.2$ 정도의 pH 변화에 의해서도 발생이 저해될 수 있다는 연구 결과는 대기중 $CO_2$ 농도 증가에 따른 해양생태계 훼손의 가능성을 더욱 높이고 있다. 반면에 대기중으로 배출되기 전에 포집된 $CO_2$ 심해처리는 처리지역 주변의 용존 이산화탄소 농도를 증가시키고 해수의 pH를 감소시켜 심해생태계를 교란할 수 있는 가능성이 높다. 따라서 심해처리 기술을 개발하는 단계에서 처리과정에서 발생할 수 있는 다양한 생물학적 위해성에 대한 충분한 검토가 필요할 것이다. 국내에서는 발광미생물과 저서단각류에 대한 용존 $CO_2$의 저해 영향에 대한 시범적인 연구가 본 연구진에 의해 수행되었는데 해수의 pH가 1.5 이상 감소한 경우에는 유의한 저해영향이 관찰됨을 알 수 있었다. 특히 단각류의 경우 동일한 pH에서도 $CO_2$로 산성화된 해수의 독성영향이 더욱 큰 것으로 나타났다. 본 논문에서는 현재까지 $CO_2$ 해양생물학적 영향에 관련하여 국내외에서 이루어진 여러 연구 결과들을 방법론에 따라 정리하였다. 이러한 연구 결과들은 향후 대기중 $CO_2$ 증가 또는 해양처리에 따른 용존 $CO_2$ 농도 증가에 따른 생태계 위해성을 예측하는 데에 이용될 수 있을 것으로 판단된다.

• 대한지역사회영양학회지
• /
• 제8권3호
• /
• pp.288-301
• /
• 2003

In order to obtain baseline data for the development of an educational program on breastfeeding, a survey was carried out to investigate infant feeding practices, the characteristics the subjects have in common, and the factors that influence the feeding methods among women in Seoul and the Chungbuk area. Subjects included 671 lactating mothers who visited public health centers or pediatric clinics between December 1999 and February 2000, and were interviewed using a questionnaire. The results were as follows : With respect to feeding methods, the incidence of breastfeeding, formula feeding, mixed feeding and formula feeding switched from breastfeeding was 20.6%, 29.8%, 11.6%, and 38.0%, respectively. With respect to the characteristics the subjects had in common, the incidence of women who planned their infants' feeding methods before pregnancy, during pregancy, and after delivery was 48.7%, 31.0％, and 20.3%, respectively. The incidence of women who started breastfeeding in the hospital after delivery was 38.8％. About seventy seven percet of the subjects had not previously attended an educational program on breastfeeding, and most of these wanted to participate in the future in an educational program to learn about breastfeeding. Some of the topics they were interested in were“Nutritional Management for Sufficient Breast Milk”(60.3%),“Breast Care”(25.0%), and“Correct Nursing Positions”(9.8%). Most (88.2%) of the women who breastfeed suffered from physical discomforts including discomfort of the waist, and legs and discomfort due to cracked or sore nipples. “Insufficient breast milk”was the main reason for breastfeeding cessation or for switching to formula feeding. With respect to formula feeding practices, the main reasons for selecting a specific brand of formula were“the same brand the hospital used after delivery”(34.3%) and“an advertised brand”(23.3%). The strongest factor for promoting breastfeeding was“the support of husband or parents”, next were “breastfeeding in the hospital after delivery”and“planning to breastfeed before pregnancy”in that order. The characteristics the subjects had in common relating to formula feeding were“mother's job”,“high economic level”,“Caesarian section”and “planning to breastfeed after delivery”. In conclusion, it is recommended that breastfeeding be pro-moted, and educational programs be developed and offered as soon as possible to each group which had unfavorable attitudes toward breastfeeding. In addition, the monitoring and supervision of formula advertisements is required to protect consumers from the adverse effects of exaggerated advertising.