• 제목/요약/키워드: repeated exposure

검색결과 247건 처리시간 0.03초

유아의 채소섭취행동 강화를 위한 채소노출 및 채소놀이 영양교육 프로그램의 효과 (Effects of Eating Behavior of Preschool Children Using a Direct Visual Stimulating Program on Vegetables and Nutrition Education with Vegetable Playing)

  • 박모라;김영진
    • 대한영양사협회학술지
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    • 제24권4호
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    • pp.298-311
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    • 2018
  • The purpose of this study was to examine 1) the relationship between the vegetable eating behavior of care givers and that of children, 2) the effectiveness of nutrition education with vegetable playing using direct visual stimulating programs on vegetable eating behavior of preschool children, and 3) the times and period of nutrition education with vegetable playing for significant changes on vegetable eating behavior. A total number of 56 individuals, aged 42 to 66 months old, participated in this study in which three kinds of vegetables (30 g)/meal were served per individual, and vegetable eating behavior was measured by the residue on the dish during 5 weeks (25 days). To the simple visual stimulating group, vegetable dish was served without education, and other groups included education 1 group (nutrition education 1 time/week), education 2 group (nutrition education 2 times/week), and education 3 group (nutrition education 3 times/week) with simple visual stimulation by the vegetable dish. The results showed 1) the significant relationship (P<0.001) between the vegetable eating behavior of the care giver and that of children by analysis of the questionnaire, 2) the effectiveness of nutrition education using vegetable playing on vegetable eating behavior of preschool children (P<0.05), and 3) the significant changes in vegetable eating behavior by the 3rd week in the education 3 group. This study shows that food neophobia caused behavior problems in children regarding vegetable eating and repeated exposure was able to reduce food neophobia.

Color stability of thermochromic pigment in maxillofacial silicone

  • Kantola, Rosita;Lassila, Lippo V.J.;Tolvanen, Mimmi;Valittu, Pekka K.
    • The Journal of Advanced Prosthodontics
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    • 제5권2호
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    • pp.75-83
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    • 2013
  • PURPOSE. Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment. MATERIALS AND METHODS. Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment, and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of $+37^{\circ}C$. Color measurements were made with a spectrophotometer and registered according to the CIELAB $L^*a^*b^*$ color model system. The changes in $L^*$, $a^*$ and $b^*$ values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant. RESULTS. The UV exposure resulted in visually noticeable and statistically significant color changes in the $L^*$, $a^*$ and $b^*$ values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the $a^*$ and $b^*$ values of the specimens containing thermochromic pigment, compared to those stored at room temperature. CONCLUSION. The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.

서울시 노원구 도로상 극미세입자 오염도 공간분포 특징 (Characteristics of spatial distribution of ultrafine particle number concentration on the roads of Nowon-gu, Seoul)

  • 이승복;이동훈;이승재;진현철;배귀남
    • 한국입자에어로졸학회지
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    • 제7권1호
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    • pp.21-30
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    • 2011
  • The spatial distributions of air pollutants, in particular, ultrafine particles near traffic congestion roads at urban areas need to reduce human exposure levels for protecting public health. In this study, the number concentrations of ultrafine particles larger than 5 nm were measured every second during driving on the major roads of Nowon-gu, Seoul for 1.6 h using a mobile emission laboratory on October 5, 2010. The ultrafine particle number concentrations ranged from 7,009 to $265,600particles/cm^3$ with an average of $55,570particles/cm^3$, and these levels were comparable to concentrations of ultrafine particles larger than 3 or 7 nm on the arterial roads at urban areas in Los Angeles, USA and Zurich, Switzerland. It was frequently observed that the ultrafine particle number increased rapidly when vehicle speed was accelerated and it decreased sharply when vehicle speed was decelerated. The high peak events of ultrafine particle concentration larger than $200,000particles/cm^3$ were observed seven times during the measurement period. From the three repeated measurements during the short period of 50 min, it was concluded that the ultrafine particle number concentration on the road was significantly time-dependent. This on-road measurement approach can be utilized to manage vehicle-related air pollution in urban.

Evaluation of softening ability of Xylene & Endosolv-R on three different epoxy resin based sealers within 1 to 2 minutes - an in vitro study

  • Shenoi, Pratima Ramakrishna;Badole, Gautam Pyarelal;Khode, Rajiv Tarachand
    • Restorative Dentistry and Endodontics
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    • 제39권1호
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    • pp.17-23
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    • 2014
  • Objectives: This study evaluated the efficacy of Endosolv-R and Xylene in softening epoxy resin based sealer after 1 to 2 min exposure. Materials and Methods: Sixty Teflon molds ($6mm{\times}1.5mm$ in inner diameter and depth) were equally divided into 3 groups of 20 each. AH 26 (Dentsply/De Trey), AH Plus (Dentsply/De Trey), Adseal (Meta-Biomed) were manipulated and placed in the molds allotted to each group and allowed to set at $37^{\circ}C$ in 100% humidity for 2 wk. Each group was further divided into 2 subgroups according to the solvents used, i.e. Xylene (Lobachemie) and Endosolv-R (Septodont). Specimens in each subgroup were exposed to respective solvents for 1 and 2 min and the corresponding Vicker's microhardness (HV) was assessed. Data was analysed by Mauchly's test and two-way analysis of variance (ANOVA) with repeated measures, and one-way ANOVA. Results: Initial hardness was significantly different among the three sealers with AH Plus having the greatest and Adseal having the least. After 2 min, Xylene softened AH Plus and Adseal sealer to 11% and 25% of their initial microhardness, respectively (p < 0.001), whereas AH 26 was least affected, maintaining 89.4% of its initial microhardness. After 2 min, Endosolv-R softened AH 26, AH Plus and Adseal to 12.7, 5.6 and 8.1% of their initial microhardness, respectively (p < 0.001). Conclusions: Endosolv-R was a significantly more effective short term softener for all the tested sealers after 2 min whereas Xylene was an effective short term softener against AH plus and Adseal but less effective against AH 26.

Evaluation of Maternal Toxicity in Rats Exposed to Multi-Wall Carbon Nanotubes during Pregnancy

  • Lim, Jeong-Hyeon;Kim, Sung-Hwan;Lee, In-Chul;Moon, Chang-Jong;Kim, Sung-Ho;Shin, Dong-Ho;Kim, Hyoung-Chin;Kim, Jong-Choon
    • Environmental Analysis Health and Toxicology
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    • 제26권
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    • pp.6.1-6.8
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    • 2011
  • Objectives: The present study investigated the potential adverse effects of multi-wall carbon nanotubes (MWCNTs) on pregnant dams and embryonic development following maternal exposure in rats. Methods: MWCNTs were orally administered to pregnant rats from gestational day (GD) 6 through 19 at dose levels of 0, 8, 40, 200, and 1000 mg/kg/day. During the test period, clinical signs, mortality, body weights, food consumption, serum biochemistry, oxidant-antioxidant status, gross findings, organ weights, and Caesarean section findings were examined. Results: All animals survived to the end of the study. A decrease in thymus weight was observed in the highest dose group. However, maternal body weight, food consumption, serum biochemical parameters, and oxidant-antioxidant balance in the kidneys were not affected by treatment with MWCNTs. No treatment-related differences in gestational index, embryo-fetal mortality, or fetal and placental weights were observed between treated and control groups. Conclusions: The results show that 14-day repeated oral dosing of MWCNTs during pregnancy induces minimal maternal toxicity at 1000 mg/kg/day in rats. Under these experimental conditions, the no-observed-adverse-effect level of MWCNTs is considered to be 200 mg/kg/day for dams and 1000 mg/kg/day for embryonic development.

Polystyrene 입자 정렬을 이용한 성게 구조 ZnO 나노막대 가스 센서의 특성 (Properties of Urchin-Structured Zinc Oxide Nanorods Gas Sensor by Using Polystyrene Sphere Array)

  • 김종우;김도훈;기태훈;박정혁;명재민
    • 한국재료학회지
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    • 제27권12호
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    • pp.658-663
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    • 2017
  • Urchin-structured zinc oxide(ZnO) nanorod(NR) gas sensors were successfully demonstrated on a polyimide(PI) substrate, using single wall carbon nanotubes(SWCNTs) as the electrode. The ZnO NRs were grown with ZnO shells arranged at regular intervals to form a network structure with maximized surface area. The high surface area and numerous junctions of the NR network structure was the key to excellent gas sensing performance. Moreover, the SWCNTs formed a junction barrier with the ZnO which further improved sensor characteristics. The fabricated urchin-structured ZnO NR gas sensors exhibited superior performance upon $NO_2$ exposure with a stable response of 110, fast rise and decay times of 38 and 24 sec, respectively. Comparative analyses revealed that the high performance of the sensors was due to a combination of high surface area, numerous active junction points, and the use of the SWCNTs electrode. Furthermore, the urchin-structured ZnO NR gas sensors showed sustainable mechanical stability. Although degradation of the devices progressed during repeated flexibility tests, the sensors were still operational even after 10000 cycles of a bending test with a radius of curvature of 5 mm.

A Case Study of the Effects of Posttraumatic Stress Disorder on Operational Fire Service Personnel Within the Lancashire Fire and Rescue Service

  • Khan, Khalid;Charters, Jonathan;Graham, Tony L.;Nasriani, Hamid R.;Ndlovu, Shephard;Mai, Jianqiang
    • Safety and Health at Work
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    • 제9권3호
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    • pp.277-289
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    • 2018
  • Background: Lancashire Fire and Rescue Service (LFRS), the subject of this evaluative research document employs 1400 people. 80% of employees are operational firefighters and officers whom operate across a range of duty systems and support functions, providing prevention, protection and emergency response to the communities of Lancashire. Methods: The overarching purpose of this epidemiological study is to assess the prevalence of posttraumatic stress disorder (PTSD) amongst operational LFRS personnel and to analyse the effects upon those who may be suffering from it, whether brought about by a single traumatic event or by repeated exposure to traumatic occurrences over a period of time. A combination of primary and secondary research was carried out. Primary data was collated using two recognised clinical questionnaires and statistical analysis was conducted with the aid of the software package SPSS. Results: The findings and statistical analysis showed that out of the 100 people surveyed, 30% of respondents had signs of probable distress. Of this quota, 4% showed symptoms of PTSD. The study considers how an organisation can recognise and manage PTSD and provides recommendations to assist in better recognising and managing the associated risks. Conclusion: Based upon the findings, the authors conclude that the level of PTSD within LFRS is slightly lower than those found in other studies undertaken within the Fire and Rescue Service sector. The paper provides recommendations for future studies and a series of actions for consideration by LFRS senior management to improve PTSD support services for employees.

응급구조원, 지하철 승무원, 아동보호전문기관 사회복지사의 대리 외상과 외상 후 성장 (Vicarious Trauma and Posttraumatic Growth in Emergency Workers, Subway Operators, and Child Protective Service Workers)

  • 이영선;이소래;주성아;고영빈;김예진;한인영
    • 사회복지연구
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    • 제43권1호
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    • pp.249-273
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    • 2012
  • 본 연구는 응급구조원, 사상 사고를 경험한 지하철승무원, 아동보호전문기관 사회복지사를 대상으로 직종, 심리적 고통, 대리 외상, 일반적 특성에 따른 외상 후 성장을 비교 분석한 연구이다. 분석 결과 첫째, 대리 외상은 세 집단 모두 위험 수준으로 높게 나타났고 특히 지하철승무원의 대리 외상이 높았으며, 외상 후 성장은 사회복지사가 가장 높고 지하철승무원이 가장 낮았다. 둘째, 대리 외상과 외상 후 성장은 상관관계가 유의한 것으로 나타났으며 특히 침습과 회피의 하위항목이 외상 후 성장과 상관관계가 높았다. 셋째, 외상 후 성장에 영향을 미치는 요인은 직종, 침습, 회피, 종교, 성별의 순서로 크게 나타났다. 본 연구에서는 이 결과를 바탕으로 대리 외상 위험 직종에 대한 정신건강서비스 제공과 외상 후 성장의 치료적 적용을 제언하였다.

노트북 거치대가 건강한 젊은 성인 손목관절근육의 생체역학적 특징에 미치는 영향 (Effects of a Notebook Computer Supporter on Biomechanical Characteristics in Wrist Joint Muscles of Healthy Young Adults)

  • 마성룡;송창순
    • PNF and Movement
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    • 제19권3호
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    • pp.391-399
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    • 2021
  • Purpose: As laptop use increases throughout the COVID-19 pandemic and its use outside of traditional workstations proliferates, it is imperative to expand the limited research available regarding ergonomic exposure. This study aimed to identify the effects of a laptop supporter on biomechanical characteristics in the wrist joint muscles of healthy young adults. Methods: This was a cross-sectional observational study design with thirty-four healthy young adults as participants. They conducted a typing exercise performed under two different conditions, which were with and without a notebook computer supporter. This study measured the biomechanical characteristics of the muscles of the wrist joints including the flexor carpi ulnaris (FCU), the flexor carpi radialis (FCR), the extensor carpi radialis longus (ECRL), and the extensor carpi ulnaris (ECU). Measurements were taken three times: before typing, immediately after typing for 30 minutes with a supporter, and immediately after typing for 30 minutes without a supporter. The statistical method to compare the three different measurement conditions was the repeated measures ANOVA. Results: The participants showed significantly different levels of dynamic stiffness in both the FCU before typing and immediately after 30 minutes of typing with a supporter, and showed significantly different levels of dynamic stiffness in the FCR before typing and immediately after 30 minutes of typing with a supporter. The dynamic stiffness level immediately after 30 minutes of typing without a supporter was significantly different than that immediately after 30 minutes of typing with a supporter. However, the muscle tone was not significantly different among the three different conditions. Conclusion: The results of this study revealed that a laptop supporter used to correct the eye level of the electronic screen increases the dynamic stiffness of the wrist joint flexors, so it is necessary to consider the neutral position of the wrist joint during typing.

치면열구전색 전후의 어린이 소변 내 Bisphenol-A의 농도 변화 (Changes in bisphenol A concentrations in urine according to sealant filling in children)

  • 신아라;김지혜;전은숙;정윤숙;송근배;최연희
    • Journal of Korean Academy of Oral Health
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    • 제41권4호
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    • pp.231-236
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    • 2017
  • Objectives: The objectives of this study were to investigate the changes in bisphenol A (BPA) concentrations in urine from before to after sealant filling and the relationship between BPA and the number of teeth with sealed surfaces. Methods: Thirty-one children aged 6 and 7 years from three elementary schools in Daegu city who did not have any sealant and resin filling were selected as subjects. Urine samples were collected before and after sealant filling until 24 hours, with informed consent from their caregivers. The BPA concentration in all the collected urine samples was analyzed at Seegene Medical. Statistical analysis was performed using the Friedman test, Scheirer-Ray-Hope test, and the repeated-measures generalized linear mixed model of SPSS version 22.0. Results: The BPA concentrations increased from $3.49-{\mu}g/g$ creatinine before to $4.91-{\mu}g/g$ creatinine 2-3 hours later and to $4.15-{\mu}g/g$ creatinine after 24 hours. The more teeth with sealed surfaces, the higher the BPA concentration in children, but the difference was not statistically significant (P>0.05). Conclusions: The BPA concentrations were highest at 2-3 hours after sealant filling and decreased at 24 hours. Exposure to the sealant appears to have a meaningful correlation with the concentration of BPA in the urine of children.