• Title/Summary/Keyword: quality factor

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Two Dimensional Size Effect on the Compressive Strength of Composite Plates Considering Influence of an Anti-buckling Device (좌굴방지장치 영향을 고려한 복합재 적층판의 압축강도에 대한 이차원 크기 효과)

  • ;;C. Soutis
    • Composites Research
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    • v.15 no.4
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    • pp.23-31
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    • 2002
  • The two dimensional size effect of specimen gauge section ($length{\;}{\times}{\;}width$) was investigated on the compressive behavior of a T300/924 $\textrm{[}45/-45/0/90\textrm{]}_{3s}$, carbon fiber-epoxy laminate. A modified ICSTM compression test fixture was used together with an anti-buckling device to test 3mm thick specimens with a $30mm{\;}{\times}{\;}30mm,{\;}50mm{\;}{\times}{\;}50mm,{\;}70mm{\;}{\times}{\;}70mm{\;}and{\;}90mm{\;}{\times}{\;}90mm$ gauge length by width section. In all cases failure was sudden and occurred mainly within the gauge length. Post failure examination suggests that $0^{\circ}$ fiber microbuckling is the critical damage mechanism that causes final failure. This is the matrix dominated failure mode and its triggering depends very much on initial fiber waviness. It is suggested that manufacturing process and quality may play a significant role in determining the compressive strength. When the anti-buckling device was used on specimens, it was showed that the compressive strength with the device was slightly greater than that without the device due to surface friction between the specimen and the device by pretoque in bolts of the device. In the analysis result on influence of the anti-buckling device using the finite element method, it was found that the compressive strength with the anti-buckling device by loaded bolts was about 7% higher than actual compressive strength. Additionally, compressive tests on specimen with an open hole were performed. The local stress concentration arising from the hole dominates the strength of the laminate rather than the stresses in the bulk of the material. It is observed that the remote failure stress decreases with increasing hole size and specimen width but is generally well above the value one might predict from the elastic stress concentration factor. This suggests that the material is not ideally brittle and some stress relief occurs around the hole. X-ray radiography reveals that damage in the form of fiber microbuckling and delamination initiates at the edge of the hole at approximately 80% of the failure load and extends stably under increasing load before becoming unstable at a critical length of 2-3mm (depends on specimen geometry). This damage growth and failure are analysed by a linear cohesive zone model. Using the independently measured laminate parameters of unnotched compressive strength and in-plane fracture toughness the model predicts successfully the notched strength as a function of hole size and width.

A Comprehensive Computer Program for Monitor Unit Calculation and Beam Data Management: Independent Verification of Radiation Treatment Planning Systems (방사선치료계획시스템의 독립적 검증을 위한 선량 계산 및 빔데이터 관리 프로그램)

  • Kim, Hee-Jung;Park, Yang-Kyun;Park, Jong-Min;Choi, Chang-Heon;Kim, Jung-In;Lee, Sang-Won;Oh, Heon-Jin;Lim, Chun-Il;Kim, Il-Han;Ye, Sung-Joon
    • Progress in Medical Physics
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    • v.19 no.4
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    • pp.231-240
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    • 2008
  • We developed a user-friendly program to independently verify monitor units (MUs) calculated by radiation treatment planning systems (RTPS), as well as to manage beam database in clinic. The off-axis factor, beam hardening effect, inhomogeneity correction, and the different depth correction were incorporated into the program algorithm to improve the accuracy in calculated MUs. A beam database in the program was supposed to use measured data from routine quality assurance (QA) processes for timely update. To enhance user's convenience, a graphic user interface (GUI) was developed by using Visual Basic for Application. In order to evaluate the accuracy of the program for various treatment conditions, the MU comparisons were made for 213 cases of phantom and for 108 cases of 17 patients treated by 3D conformal radiation therapy. The MUs calculated by the program and calculated by the RTPS showed a fair agreement within ${\pm}3%$ for the phantom and ${\pm}5%$ for the patient, except for the cases of extreme inhomogeneity. By using Visual Basic for Application and Microsoft Excel worksheet interface, the program can automatically generate beam data book for clinical reference and the comparison template for the beam data management. The program developed in this study can be used to verify the accuracy of RTPS for various treatment conditions and thus can be used as a tool of routine RTPS QA, as well as independent MU checks. In addition, its beam database management interface can update beam data periodically and thus can be used to monitor multiple beam databases efficiently.

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Criteria of Evaluating Clothing and Web Service on Internet Shopping Mall Related to Consumer Involvement (인터넷 쇼핑몰 이용자의 소비자 관여에 따른 의류제품 및 웹 서비스 평가기준에 관한 연구)

  • Lee, Kyung-Hoon;Park, Jae-Ok
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.12 s.159
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    • pp.1747-1758
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    • 2006
  • Rapid development of the information technology has influenced on the changes in every sector of human environments. One prominent change in retail market is an increase of electronic stores, which has prompted practical and research interest in the product and store attributes that include consumer to purchase products from the electronic shopping. Therefore many marketers are paying much attention to the criteria of evaluating clothing and web service on internet shopping malls. The purpose of this study is to examine differences of clothing and web service criteria of consumer groups (High-Involvement & High-Ability, Low-Involvement & High-Ability, High-Involvement & Low-Ability, and Low-Involvement & Low-Ability) who are classified into consumer involvement and internet use ability. The subjects of this study were 305 people aged between 19 and 39s, living in Seoul and Gyeonggi-do area, and having experiences in buying products on the internet shopping. Statistical analyses used for this study were the frequency, percentage, factor analysis, ANOVA and Duncan test. The results of this study were as follows: Regarded on the criteria of evaluating clothing, the low different groups had significant differences in the esthetic, the quality performance and the extrinsic criterion. Both HIHA group and HILA group showed the similar results. They considered every criterion of evaluating clothing more important, compared with other groups. Regarded on the criteria of evaluating web service related to the low different groups, there were significant differences in the factors related to the shopping mall reliance, the product, the satisfaction after purchase, and the promotion and policy criterion. Both HIHA group and HILA group showed the similar results as well. They considered every criterion of evaluating web service more important, compared with other groups. In conclusion, HI groups perceive relatively more dangerous factors which can be occurred during internet shopping. Therefore, internet shopping malls need to provide clothing that can satisfy the HI groups as well as make efforts to remove the dangerous factors on the internet.

Effect of Silicate-Coated Rice Seed on Healthy Seedling Development and Bakanae Disease Reduction when Raising Rice in Seed Boxes (벼 상자육묘에서 규산코팅볍씨의 건묘육성과 벼키다리병 경감효과)

  • Kang, Yang-Soon;Kim, Wan Jung;Roh, Jae-Hwan
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.62 no.1
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    • pp.1-8
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    • 2017
  • We investigated the effect of silicate coating of rice seeds on bakanae disease incidence and the quality of seedlings raised in seedling boxes and transplanted into pots. The silicate-coated rice seed (SCS) was prepared as follows. Naturally infested rice seeds not previously subjected to any fungicidal treatment were dressed with a mixture of 25% silicic acid at pH 11 and 300-mesh zeolite powder at a ratio of 50 g dry seed - 9 mL silicic acid - 25 g zeolite powder. The following nursery conditions were provided : Early sowing, dense seeding in a glass house with mulching overnight and no artificial heating, which were the ideal conditions for determining the effect on the seed. The nursery plants were evaluated for Gibberella. fujikuroi infection or to determine the recovery to normal growth of infected nursery plants in the Wagner pot. Seedlings emerged 2-3 days earlier for the SCS than they did for the non-SCS control, while damping-off and bakanae disease incidence were remarkably reduced. Specifically, bakanae disease incidence in the SCS was limited to only 7.8% for 80 days after sowing, as compared to 91.6% of the non-SCS control. For the 45-days-old SCS nursery seedlings, the fresh weight was increased by 11% and was two times heavier, with only mild damage compared to that observed for non-SCS. Even after transplanting, SCS treatment contributed to a lower incidence of further infections and possibly to recovery of the seedlings to normal growth as compared to that observed in symptomatic plants in the pot. The active pathogenic macro-conidia and micro-conidia were considerably lower in the soil, root, and seedling sheath base of the SCS. In particular, the underdeveloped macro-conidia with straight oblong shape without intact septum were isolated in the SCS ; this phenotype is likely to be at a comparative etiological disadvantage when compared to that of typical active macro-conidia, which are slightly sickle-shaped with 3-7 intact septa. A active intact conidia with high inoculum potential were rarely observed in the tissue of the seedlings treated only in the SCS. We propose that promising result was likely achieved via inhibition of the development of intact pathogenic conidia, in concert with the aerobic, acidic conditions induced by the physiochemical characteristics associated with the air porosity of zeolite, alkalinity of silicate and the seed husk as a carbon source. In addition, the resistance of the healthy plants to pathogenic conidia was also important factor.

The Effect of Psychological Factors on Postoperative Pain in Gastric Tumor Patients after Endoscopic Submucosal Dissection (내시경 점막하 박리법을 시술 받은 위종양 환자에서 심리적 요인이 시술 후 통증에 미치는 영향)

  • Lee, Joon-Hyub;Jeon, Han Ho;Lee, San;Lee, Hyeok;Oh, Seung-Taek;Chang, Jhin Goo;Im, Woo Young;Park, Jaesub;Choi, Won-Jung
    • Korean Journal of Psychosomatic Medicine
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    • v.26 no.1
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    • pp.68-75
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    • 2018
  • Objectives : Since pain in cancer patients is an important factor that greatly affects the quality of life and prognosis, many attempts have been actively made to reduce the pain. Despite continuous effort on reducing pain after Endoscopic submucosal dissection (ESD), research has not been done on psychological factors as much as on biological factors affecting pain. The objective of this study is to investigate the psychological factors affecting postoperative pain in gastric tumor patients who underwent gastric ESD. Methods : 91 gastric tumor patients who visited National Health Service Ilsan Hospital in Korean between May 2015 and June 2016, and received ESD were evaluated. Baseline characteristics including sociodemographic factors, anxiety, depression, and resilience were evaluated before the procedure. Multivariate logistic regression was done to analyze factors affecting postoperative pain. Results : The group with high postoperative pain showed lower alcohol consumption and higher depressive symptom scores than the group with low postoperative pain. Also, the group with high postoperative pain showed lower total resilience score with lower subtotal scores in self-control and positive item. Multivariate logistic regression analysis of the postoperative pain showed that patients with lower score in self-control of resilience [odd ratio (OR), 0.911 ; 95% CI, 0.854-0.971, p=0.004) reported more pain after ESD. Conclusions : This study showed that patients with lower self-control ability of resilience felt more pain after ESD. Among the psychological factors evaluated in this study, resilience of an individual seems to have effect on pain.

The Study of Factor Concerning Ovum Pick-up and Conception Rate by Ultrasound-Guided Follicular Aspiration in Hanwoo Heifers (한우에 있어서 초음파기기를 이용한 생체내 난자 채취시 채란조건 및 수태율에 관한 연구)

  • 박성재;양보석;임기순;성환후;장원경;정일정;박충생
    • Korean Journal of Animal Reproduction
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    • v.24 no.2
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    • pp.199-208
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    • 2000
  • This study was carried out to investigate of factors concerning to ultrasound-guided follicular aspiration; level of vacuum pressure, diameter of use needle, effect of FSH hormone and conception rate after embryos transfer. 1. Oocytes collection number were 4.2$\pm$2.9 e.a to luteuml phase and follicular phase were 4.4$\pm$3.5 e.a to ovaries of Hanwoo. 2. We taked proper level of aspiration vacuum pressure was 40~120 mmHg to oocytes collection. Oocytes collected number were 4.2$\pm$3.2, 4.3$\pm$3.4, 4.5$\pm$3.4 e.a. to 40, 80, 120mmHg, respectively, follicles aspiration rate were 49, 47, 45%. 3. Effect of collection needle diameter was not difference significantly(P<0.05), oocytes collected number were 4.4$\pm$3.5 e.a to 170 and 3.0$\pm$1.8 e.a to 18G needle, collected oocytes quality were no difference significantly (P<0.05). 4. Follicles increase number to FSH hormone injection were 6.2$\pm$2.3 e.a to intramuscle and 1.1$\pm$2.7 e.a. to epithelial injection method. 5. Conception rate derived from E.T. was 11.1% to freezing embryos and 46.2% to fresh E.T., difference significantly(P<0.05).

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Chemical characteristics of wet precipitation in urban and mountainous sites of Jeju Island

  • Bu, Jun-Oh;Song, Jung-Min;Park, Sook-Young;Kang, Hee-Ju;Kang, Chang-Hee
    • Analytical Science and Technology
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    • v.33 no.1
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    • pp.33-41
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    • 2020
  • Wet precipitation samples were collected in Jeju City and Mt. Halla-1100 site (a site at an altitude of 1100 m on Mt. Halla) during 2011-2013, and their major ionic species were analyzed to examine the chemical composition and characteristics. A comparison of ion balance, electric conductivity, and acid fraction of precipitation revealed correlation coefficients in the range of r = 0.950~0.991, thereby implying the high quality of analytical data. Volume-weighted mean pH and electric conductivity corresponded to 4.86 and 25.5 µS/cm for Jeju City, and 4.98 and 15.1 µS/cm for Mt. Halla-1100 site, respectively. Ionic strengths of the wet precipitation in Jeju City and Mt. Halla-1100 site corresponded 0.3 ± 0.5 and 0.2 ± 0.2 mM, respectively, thereby indicating that more than 30 % of total precipitation was within a pure precipitation criteria. The precipitation with a pH range of 4.5 - 5.0 corresponded to 40.8 % in Jeju City, while the precipitation with a pH range of 5.0 - 5.5 corresponded to 56.9 % in Mt. Halla-1100 site, thereby indicating slightly more weak acidity than that in Jeju city. The volume-weighted mean concentration (µeq/L) of ionic species was in the order of Na+ > Cl- > nss-SO42- > NO3- > Mg2+ > NH4+ > H+ > nss-Ca2+ > PO43- > K+ > CH3COO- > HCOO- > NO2- > F- > HCO3- > CH3SO3- at Jeju City area, while it corresponded to Na+ > Cl- > nss-SO42- > NO3- > NH4+ > H+ > Mg2+ > nss-Ca2+ > PO43- > CH3COO- > K+ > HCOO- > NO2- > F- > HCO3- > CH3SO3- at Mt. Halla-1100 site. The compositions of sea salts (Na+, Cl-, Mg2+) and secondary pollutants (NH4+, nss-SO42-, NO3-) corresponded to 66.1 % and 21.8 %, respectively, in Jeju City and, 49.9 % and 31.5 %, respectively, in Mt. Halla-1100 site. The acidity contributions in Jeju City and Mt. Halla-1100 site by inorganic acids, i.e., sulfuric acid and nitric acid, corresponded to 93.9 % and 91.4 %, respectively, and the acidity contributions by organic acids corresponded to 6.1 % and 8.6 %, respectively. The neutralization factors in Jeju City and Mt. Halla1100 site by ammonia corresponded to 29.8 % and 30.1 %, respectively, whereas the neutralization factors by calcium carbonate corresponded to 20.5 % and 25.2 %, respectively. From the clustered back trajectory analysis, the concentrations of most ionic components were higher when the airflow pathways were moved from the continent to Jeju area.

Removal Characteristics of Nitrogenous Organic Chlorination Disinfection By-Products by Activated Carbons and Biofiltration (활성탄과 생물여과 공정에서의 유기질소계 염소 소독부산물 제거 특성)

  • Seo, In-Suk;Son, Hee-Jong;Choi, Young-Ik;Ahn, Wook-Sung;Park, Chung-Kil
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.2
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    • pp.184-191
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    • 2007
  • Coal-, coconut- and wood-based activated carbons and anthracite were tested for an adsorption and biodegradation performances of nitrogenous chlorinated by-products such as chloropicrin, DCAN, DBAN and TCAN. In early stage of operations, an adsorption performance was a main mechanism for removal of nitrogenous chlorinated by-products, however as increasing populations of attached bacteria, the bacteria played a major role in removing nitrogenous chlorinated by-products in the activated carbon and anthracite biofilter. It was also investigated that the compounds were readily subjected to biodegrade. Whilst the coal- and coconut-based activated carbons were found most effective in adsorption of the compounds, the anthracite was worst in adsorption of the compounds. Highest populations and activity of attached bacteria were shown in the coal-based activated carbon. The populations and activity of attached bacteria decreased in the order: coconut-based activated carbon > wood-based activated carbon > anthracite. The attached bacteria were inhibited for removal of the compounds at temperatures below $10^{\circ}C$. The attached bacteria were more active at higher water temperatures$(20^{\circ}C\;<)$ but less active at love. water temperature$(10^{\circ}C\;>)$. The removal efficiencies of the compounds obtained using coal-, coconut- and wood-based activated carbons and anthracite were directly related to the water temperatures. In particular, water temperature was the most important factor for removal of the compounds in the anthracite biofilter because the removal of the compounds depended mainly on biodegradation. Therefore, the main removal mechanism of the compounds the main mechanism on the removal of the compounds using activated carbon was both adsorption and biodegradation by the attached bacteria. The observation suggests that using coal-based activated carbon is the best for removal of nitrogenous chlorinated by-products in the water treatment.

Distributions of Organic Matter and Heavy Metals in the Surface Sediment of Jaran Bay, Korea (자란만 표층 퇴적물 중 유기물과 중금속 농도분포)

  • Hwang, Hyunjin;Hwang, Dong-Woon;Lee, Garam;Kim, Hyung-Chul;Kwon, Jung-No
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.1
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    • pp.78-91
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    • 2018
  • In order to understand the distributions of organic matter and heavy metal concentrations in the surface sediment of Jaran Bay, we measured the grain size, total organic carbon (TOC), total nitrogen (TN), and heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn) in surface sediments collected at 15 stations in this bay in November 2014. The sediment consisted of finer sediment such as mud and clay, with 8.6-9.8Ø($9.3{\pm}0.3$Ø) of mean grain size. The concentrations of TOC and TN in the sediment ranged from 1.51-2.39 % ($1.74{\pm}0.22%$) and 0.20-0.33 % ($0.23{\pm}0.03%$), respectively, and did not show spatial difference. The carbon to nitrogen ratio (C/N ratio) ranged from 5-10, indicating that organic matter in the sediment originated from oceanic sources such as animal by-products from fish and shellfish farms. The concentrations of Cr, Fe, and Mn were much higher in the mouth of the bay than in the inner bay, and the concentrations of As, Cd, Cu, Hg, Pb, and Zn showed an opposite distribution pattern. Based on the results of the sediment quality guidelines (SQGs), enrichment factor (EF), geoaccumulation index ($I_{geo}$), pollutant load index (PLI), and ecological risk index (ERI), the surface sediment in Jaran Bay is not polluted or only slightly polluted with Cd, Cr, Cu, Hg, Pb, and Zn, whereas it is moderately to strongly polluted with As. In particular, some regions in the bay were identified as having a considerable risk status, indicating that metal concentration in the sediment could impact benthic organisms. Thus, the systematic management for marine and land sources of organic matter and heavy metals around Jaran Bay is necessary in order to ensure seafood safety and maintain sustainable production on shellfish farms.

ATHEROSCLEROSIS, CHOLESTEROL AND EGG - REVIEW -

  • Paik, I.K.;Blair, R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.9 no.1
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    • pp.1-25
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    • 1996
  • The pathogenesis of atherosclerosis can not be summarized as a single process. Lipid infiltration hypothesis and endothelial injury hypothesis have been proposed and investigated. Recent developments show that there are many points of potential interactions between them and that they can actually be regarded as two phases of a single, unifying hypothesis. Among the many risk factors of atherosclerosis, plasma homocysteine and lipoprotein(a) draw a considerable interest because they are independent indicators of atherogenicity. Triglyceride (TG)-rich lipoproteins (chylomicron and VLDL) are not considered to be atherogenic but they are related to the metabolism of HDL cholesterol and indirectly related to coronary heart disease (CHD). LDL can of itself be atherogenic but the oxidative products of this lipoprotein are more detrimental. HDL cholesterol has been considered to be a favorable cholesterol. The so-called 'causalist view' claims that HDL traps excess cholesterol from cellular membranes and transfers it to TG-rich lipoproteins that are subsequently removed by hepatic receptors. In the so-called 'noncausalist view', HDL does not interfere directly with cholesterol deposition in the arterial wall but instead reflects he metabolism of TG-rich lipoproteins and their conversion to atherogenic remnants. Approximately 70-80% of the human population shows an effective feedback control mechanism in cholesterol homeostasis. Type of dietary fat has a significant effect on the lipoprotein cholesterol metabolism and atherosclerosis. Generally, saturated fatty acids elevate and PUFA lower serum cholesterol, whereas MUFA have no specific effect. EPA and DHA inhibit the synthesis of TG, VLDL and LDL, and may have favourable effects on some of the risk factors. Phospholipids, particularly lecithin, have an antiatherosclerotic effect. Essential phospholipids (EPL) may enhance the formation of polyunsaturated cholesteryl ester (CE) which is less sclerotic and more easily dispersed via enhanced hydrolysis of CE in the arterial wall. Also, neutral fecal steroid elimination may be enhanced and cholesterol absorption reduced following EPL treatment. Antioxidants protect lipoproteins from oxidation, and cells from the injury of toxic, oxidized LDL. The rationale for lowering of serum cholesterol is the strong association between elevation of plasma or serum cholesterol and CHD. Cholesterol-lowing, especially LDL cholesterol, to the target level could be achieved using diet and combination of drug therapy. Information on the link between cholesterol and CHD has decreased egg consumption by 16-25%. Some clinical studies have indicated that dietary cholesterol and egg have a significant hypercholesterolemic effect, while others have indicated no effect. These studies differed in the use of purified cholesterol or cholesterol in eggs, in the range of baseline and challenge cholesterol levels, in the quality and quantity of concomitant dietary fat, in the study population demographics and initial serum cholesterol levels, and clinical settings. Cholesterol content of eggs varies to a certain extent depending on the age, breed and diet of hens. However, egg yolk cholesterol level is very resistant to change because of the particular mechanism involved in yolk formation. Egg yolk contains a factor of factors responsible for accelerated cholesterol metabolism and excretion compared with crystalline cholesterol. One of these factors could be egg lecithin. Egg lecithin may not be as effective as soybean lecithin in lowering serum cholesterol level due probably to the differences of fatty acid composition. However, egg lecithin may have positive effects in hypercholesterolemia by increasing serum HDL level and excretion of fecal cholesterol. The association of serum cholesterol with egg consumption has been widely studied. When the basal or control diet contained little or no cholesterol, consumption of 1 or 2 eggs daily increased the concentration of plasma cholesterol, whereas that of the normolipemic persons on a normal diet was not significantly influenced by consuming 2 to 3 eggs daily. At higher levels of egg consumption, the concentration of HDL tends to increase as well as LDL. There exist hyper-and hypo-responders to dietary (egg) cholesterol. Identifying individuals in both categories would be useful from the point of view of nutrition guidelines. Dietary modification of fatty acid composition has been pursued as a viable method of modifying fat composition of eggs and adding value to eggs. In many cases beneficial effects of PUFA enriched eggs have been demonstrated. Generally, consumption of n-3 fatty acids enriched eggs lowered the concentration of plasma TG and total cholesterol compared to the consumption of regular eggs. Due to the highly oxidative nature of PUFA, stability of this fat is essential. The implication of hepatic lipid accumulation which was observed in hens fed on fish oils should be explored. Nutritional manipulations, such as supplementation with iodine, inhibitors of cholesterol biosynthesis, garlic products, amino acids and high fibre ingredients, have met a limited success in lowering egg cholesterol.