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Ecophysiological Studies on the Population Dynamics of Two Toxic Dinoflagellates Alexandrium tamarense and Alexandrium catenella Isolated from the Southern Coast of Korea -I. Effects of Temperature and Salinity on the Growth (남해연안해역에서 분리한 유독와편모조류 Alexandrium tamarense와 Alexandrium catenella의 개체군 변화에 관한 생리.생태학적 연구 -I. 수온과 염분의 변화에 따른 성장 특성)

  • Oh, Seok-Jin;Park, Ji-A;Kwon, Hyeong-Kyu;Yang, Han-Soeb;Lim, Weol-Ae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.2
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    • pp.133-141
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    • 2012
  • Effects of temperature and salinity on the growth of the toxic dinoflagellate $Alexandrium$ $tamarense$ and $A.$ $catenella$ isolated from the southern coast of Korea were examined in the laboratory. Growth experiment was conducted under the following combinations of temperature and salinity; 10, 15, 20, 25 and $30^{\circ}C$, 10, 15, 20, 25, 30 and 35 psu at a constant irradiance of 300 ${\mu}mol$ photons $m^{-2}s^{-1}$. Temperature and salinity conditions for maximum growth rate were indicated as follows: temperature $15^{\circ}C$ and salinity 30 psu (0.31 $d^{-1}$) in $A.$ $tamarense$, temperature $25^{\circ}C$ and salinity 30 psu (0.36 $d^{-1}$) in A. catenella. Temperature and salinity ranges for optimum growth condition of two species were $10{\sim}20^{\circ}C$, 25~35 psu and $120{\sim}30^{\circ}C$, 25~35 psu, respectively. The result of two-factor ANOVA indicated significant effects (P<0.001) of temperature and salinity on the growth rate, and two species were more effected by a temperature than a salinity on the growth. In addition, prediction equations were obtained through the multiple regressions of the specific growth rates as ${\mu}=0.04+0.0193T-0.0339S- 0.0005T^2+0.0021S^2+0.00073TS-0.000022T^3-0.000038S^3+0.00000086TS^2-0.0000255T^2S$ in $A.$ $tamarense$ and ${\mu}=1.01-0.1288T-0.0778S+0.0067T^2+0.0038S^2+0.00204TS-0.0001T^3-0.000059S^3-0.0000131TS^2-0.0000392T^2S$ in $A.$ $catenella$. Correlation coefficient between experimental values and simulated values was highly indicated. These results seem to provide information for understanding the spreading mechanism of $A.$ $tamarense$ and $A.$ $catenella$.

Effects of Herbicides on the Growth, Nodulation and VA Mycorrhizal Infection in Soybean (Glycine max) (제초제(除草劑) 처리(處理)가 콩 생육(生育) 및 근류균(根瘤菌) 착생(着生)과 VA 균근균(菌根菌) 감염(感染)에 미치는 영향(影響))

  • Yoon, C.S.;Huh, S.M.;Shon, B.K.
    • Korean Journal of Weed Science
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    • v.12 no.1
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    • pp.16-30
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    • 1992
  • A field experiment was done to evaluate the growth response, rhizobia nodulation and vesicular-arbuscular mycorrhizal fungi (VAMF) infection of soybean treated with the different concentration of three-herbicides, alachlor, simazine, linuron. The results obtained were summarized as follows ; Emergence rate of soybean was non-significantly decreased by increasing the herbicide concentration. In simazine treatment, low emergence rate showed even in recommended concentration, especially the lowest emergence rate in treble concentration of recommended dose was about 50%. The plant length of soybean lowered by increasing the herbicide concentration, but there were almost no differences in recommended dose. Particularly that in a high concentration of herbicides at three weeks after treatment(WAT) was decreased remarkably. In the plant diameter of soybean shoot, no differences in the recommended concentration of alachlor and linuron at 2 WAT, but those of recommended dose was decreased with the lapse of time, and the lowest treatment was simazine-treated plot. Leaf area and fresh weight of soybean tended to decrease over the control even in recommended concentration and it was decreased with the increment of the herbicide dose. Yield component, fresh weight of rhizobia nodule and chlorophyll content of soybean leaves were reduced with the increment of herbicide dose, espicially remarkable tendency was revealed in simazine-treated plot. Seasonal infection rate of VAM showed a slight decrease by increasing of herbicide dose, and the lowest infection was simazine treatment. Significant correlation was realized among the reduction of rhizobia nodulation, VAM colonization and the agronomic characters of soybean and it was considered that the reduction of rhizobia nodulation and VAM colonization by misapplication of the herbicides might be a causal factor for decrease in soybean yield.

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Use of Human Adipose Tissue as a Source of Endothelial Cells (혈관내피세포 채취의 원천으로 인간 지방조직의 활용)

  • Park, Bong-Wook;Hah, Young-Sool;Kim, Jin-Hyun;Cho, Hee-Young;Jung, Myeong-Hee;Kim, Deok-Ryong;Kim, Uk-Kyu;Kim, Jong-Ryoul;Jang, Jung-Hui;Byun, June-Ho
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.4
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    • pp.299-305
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    • 2010
  • Purpose: Adipose tissue is located beneath the skin, around internal organs, and in the bone marrow in humans. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. Adipose tissue also has the ability to dynamically expand and shrink throughout the life of an adult. Recently, it has been shown that adipose tissue contains a population of adult multipotent mesenchymal stem cells and endothelial progenitor cells that, in cell culture conditions, have extensive proliferative capacity and are able to differentiate into several lineages, including, osteogenic, chondrogenic, endothelial cells, and myogenic lineages. Materials and Methods: This study focused on endothelial cell culture from the adipose tissue. Adipose tissues were harvested from buccal fat pad during bilateral sagittal split ramus osteotomy for surgical correction of mandibular prognathism. The tissues were treated with 0.075% type I collagenase. The samples were neutralized with DMEM/and centrifuged for 10 min at 2,400 rpm. The pellet was treated with 3 volume of RBC lysis buffer and filtered through a 100 ${\mu}m$ nylon cell strainer. The filtered cells were centrifuged for 10 min at 2,400 rpm. The cells were further cultured in the endothelial cell culture medium (EGM-2, Cambrex, Walkersville, Md., USA) supplemented with 10% fetal bovine serum, human EGF, human VEGF, human insulin-like growth factor-1, human FGF-$\beta$, heparin, ascorbic acid and hydrocortisone at a density of $1{\times}10^5$ cells/well in a 24-well plate. Low positivity of endothelial cell markers, such as CD31 and CD146, was observed during early passage of cells. Results: Increase of CD146 positivity was observed in passage 5 to 7 adipose tissue-derived cells. However, CD44, representative mesenchymal stem cell marker, was also strongly expressed. CD146 sorted adipose tissue-derived cells was cultured using immuno-magnetic beads. Magnetic labeling with 100 ${\mu}l$ microbeads per 108 cells was performed for 30 minutes at $4^{\circ}C$ a using CD146 direct cell isolation kit. Magnetic separation was carried out and a separator under a biological hood. Aliquous of CD146+ sorted cells were evaluated for purity by flow cytometry. Sorted cells were 96.04% positivity for CD146. And then tube formation was examined. These CD146 sorted adipose tissue-derived cells formed tube-like structures on Matrigel. Conclusion: These results suggest that adipose tissue-derived cells are endothelial cells. With the fabrication of the vascularized scaffold construct, novel approaches could be developed to enhance the engineered scaffold by the addition of adipose tissue-derived endothelial cells and periosteal-derived osteoblastic cells to promote bone growth.

A Study on Clothing purchase Behavior through internet of Middle and High School Students (${\cdot}$고등학생들의 인터넷을 이용한 의복 구매 행동 연구)

  • Kweon Li-Ra;Kim Mi-Jeong;Lee hye-Ja;Yu Nan-Sook
    • Journal of Korean Home Economics Education Association
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    • v.17 no.2
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    • pp.29-47
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    • 2005
  • In this study. we tried to provide basic materials for teachers to develop consumer's guide of internet shopping for middle and high school students through surveying their Purchase realities, clothing purchase behaviors. and clothing purchase attitudes when they use internet shopping mall. The questionaires were distributed to middle and high school students in Seoul, Daegu, Kyunggi, Chungbuk, Chungnam, Kyungbuk, and Kyungnam November, 2004. The followings are the results of this study. First, clothing items which were bought in internet shopping malls were shirts. shoes, pants, bags in order and they were below $20,000\~30,000$ won. Main payment method used was sending money to seller's account. Second, clothing purchase satisfaction degree was comparatively high but the satisfaction degree for the compensation policy was low. If they had any claims for the products. they were likely to behave more actively than passively. Third. returned items were shirts, pants, shoes in order which are the same as purchasing items and they were due to the size and the difference between the products recognised by computer screen and the real products. The $89.0\%$ of the subjects who have purchased clothing through internet expressed high intention to purchase in the future through internet. Forth the degree of attitude toward the internet shopping concerned with clothing purchase was high in the factor of 'convenience of shopping', especially they thought that the purchase through internet had the advantage of varieties and prices. The significant differences were found (1) in the experience of purchase and clothing purchase through internet according to their regions. school years, allowances per month, (2) in the purchased items through internet according to only their sexes, and (3) in the desired Purchase items through internet according to school years, their sexes. regions. The more frequently the middle and high school students use internet, the more goods they purchase through internet, especially the portion of the purchased clothing is getting bigger year by year. This suggests that we need to develope well-organized programs to teach good consumer's attitude to the middle and high school students when they purchase through internet.

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Effect of Epigallocatechin Gallate on Phosphoinositide 3-kinase/Akt and Glycogen Synthase Kinase-3 Pathway in Oxidative-stressed N18D3 Cells Following $H_2O_2$ Exposure (산화성 손상을 받은 N18D3세포에서 Epigallocatechin gallate가 Phosphoinositide 3-kinase/Akt 및 Glycogen synthase kinase-3경로에 미치는 효과)

  • Koh, Seong Ho;Kwon, Hyug Sung;Oh, Hwa Soon;Oh, Jae Ho;Park, Ynun Joo;Kim, Jun Gyou;Kim, Ki Sok;Kim, Yang Soon;Yang, Ki Hwa;Kim, Seung U.;Kim, Seung H.;Jung, Hai Kwu
    • Korean Journal of Clinical Pharmacy
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    • v.13 no.1
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    • pp.29-39
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    • 2003
  • Neurodegenerative disorders are associated with apoptosis as a causing factor or an inducer. On the other hand, it has been reported that epigallocatechin gallate (EUG), one of antioxidants and flavonoids, and z-VAD-fmk, a nonselective caspase inhibitor, suppress oxidative-radical-stress-induced apoptosis. However, it is not yet known what is the effects of EGCG and z-VAD-fmk on the apoptotic pathway is through phosphoinositide 3-kinase (PI3K), Akt and glycogen synthase kinase-3 (GSK-3) as well as mitochondria, caspase-3 and poly (ADP-ribose) polymerase (PARP). We investigated the effects of EGCG by using $H_2O_2$ treated N18D3 cells, mouse DRG hybrid neurons. Methods: Following 30 min $100\;{\mu}m\;H_2O_2$ exposure, the viability of N18D3 cells (not pretreated vs. EGCG or z-VAD-fmk pretreated) was evaluated by using MTT assay. The effect of EGCG on immunoreactivity (IR) of cytochrome c, caspase-3, PARP, PI3K/Akt and GSK-3 was examined by using Western blot, and was compared with that of z-Y4D-fmk. Results: EGCG or z-VAD-fmk pretreated N18D3 cells showed increased viability. Dose-dependent inhibition of caspase-3 activation accompanied by PARP cleavage were demonstrated by pretreatment of both agents. However, inhibition of cytochrome c release was only detected in EGCG pretreated N18D3 cells. On the pathway through PI3K/Akt and GSK-3, however, the result of Western blot in EGCG pretreated N18D3 cells showed decreased IR of Akt and GSK-3 and increased IR of p85a PI3K, phosphorylated Akt and GSK-3, and contrasted with that in z-VAD-fmk pretreated N18D3 cells showing no changes on each molecule. Conclusion: These data show that EGCG affects apoptotic pathway through upstream signal including PI3K/Akt and GSK-3 pathway as well as downstream signal including cytochrome c and caspase-3 pathway. Therefore, these results suggest that EGCG mediated activation of PI3K/Akt and inhibition GSK-B could be new potential therapeutic strategy for neurodegenerative diseases associated with oxidative injury.

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Alcohol Intake in Relation to Cardiovascular Risk Factors among (Middle Age) South Korean Men (한국의 중년기 남성의 심혈관계 질환 위험요인과 음주섭취와의 관련성)

  • Park, Kyung-Min
    • Research in Community and Public Health Nursing
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    • v.9 no.1
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    • pp.232-241
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    • 1998
  • 음주습관과 심혈관계 질환 위험요인사이의 관련성을 파악하기 위하여, 1996년 한국 경북에 있는 도시지역 한 철강회사에서 40-50대(40-59세) 남자 근로자 3444명으로부터 공복시 혈액을 10m1 채취하여 혈청지질, 혈당, Uric acid를 측정하고 신장, 체중, 혈압(10-20분 휴식후 측정)과 EKG를 측정하였다. 과거병력, 현재 건강상태, 음주량과 기간 및 음주종류를 포함한 생활습관, 흡연량/일, 운동시간/주 등의 설문지를 작성하였다. 알콜 소비량은 양-빈도의 Index에 의해 측정되었다. 한국 중년 남자에 대한 음주량, 음주기간, 알콜종류등에 따른 심혈관계 질환의 위험요인 유무 정도를 알아보기 위해, 비음주자를 기준으로하여 비교대상군은 금주자와 음주량(2군) 등에 의해 3군으로 분류하였으며, 음주기간에 따른 심혈관계 질환의 위험요인 유무정도를 알아보기 위해 비음주자을 기준으로하여 비교 대상군은 금주자와 음주기간(4군)에 따라 5군으로 분류하였다. 알콜종류에 따른 심혈관계 질환의 위험요인 유무정도를 알아보기 위해 비음주자을 기준으로하여 비교 대상군은 금주자와 음주알콜종류(3군)에 따라 4군으로 분류하였다. 심혈관계 질환 위험요인은 기준되는 범주를 2개(Table 1)로 분류하여 2*2표를 이용하여 odds ratio(dummy variable로 처리), ${\beta}$-coefficient와 표준오차를 이용해서 신뢰구간(95% C.I.)을 구하여 유의성 검정을 하였다. 금주자의 정의는 과거 3달 이상 술을 마시지 않는 사람을 말한다. 연구 집단의 평균 연령은 $44.4{\pm}3.9$세 이며, 비음주자는 649명으로 18.9%, 금주자는 70명(2.0%)이며 음주자는 2725명(79.1%)이다. 음주자중 에타놀 섭취를 평균 100.5g/주(median) 미만인 군은 1239명으로 연구집단 3444명중 35.7%이며, 평균 100.5g/주(median) 이상 음주군은 1276명으로 44.5%이었다. 3444명중 1532명(44.5%) 이 맥주와 소주를 섞어서 마시는 사람이었다. 음주 양에서, 연령, 흡연 양, 흡연 기간, 운동, 음주기간, 알콜종류 등을 통제하여 logistic regression한 결과, 비음주자에 비해 중정도 음주자(${\ge}$100.5gm/week ethanol)의 확장기 혈압의 Odds ratio는 1.33배로 유의하게 높았다(P<0.05). 다른 요인들은 통계적으로 유의한 차이를 보이지 않았다. 알콜종류에서도 연령, 흡연 양, 흡연 기간, 운동, 음주양, 음주기간, 등을 통제한, 비음주자에 비해 맥주와 소주를 섞어 마시는 음주자의 확장기 혈압의 Odds ratio는 1.38배로 유의하게 높았다(P<0.01). 다른 요인들은 통계적으로 유의한 차이를 보이지 않았다. 반면에 음주 습관 중 음주기간에서는 연령, 흡연양, 흡연 기간, 운동, 음주양, 알콜종류 등을 통제한 logistic regression 분석 결과 유의한 차이를 보인 것은 없었다. 그러나 음주기간과 심혈관계 질환 위험요인중 수축기와 확장기 혈압과의 관계는 J 모양을 나타내었다 . 수축기 혈압의 금주자군은 비차비가 1.0보다 약간 낮고(Odds ratio=0.88) 음주기간이 2-10년인 군의 Odds ratio=1.14, 음주기간이 11-20 년인군의 Odds ratio =1.18, 21년 이상인 군의 Odds ratio=1.20로 비음주자의 odds ratio=1에 비해 점차적으로 위험이 높아졌다. 확장기 혈압의 금주자군은 비차비가 1.0보다 약간 낮고(Odds ratio=0.91), 음주기간이 1년 이하인 군의 Odds ratio=1.18, 음주기간이 2-10 년인 군의 Odds ratio=1.23, 음주기간이 11-20 년인 군의 Odds ratio=1.27, 21년 이상인 군의 Odds ratio=1.27로 비음주자의 odds ratio=1에 비해 점차적으로 위험이 높아졌다.

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Changes of the Preoperative and Postoperative Nutritional Statuses in Patients with Gastric Cancer and Assessment of the Nutritional Factors That Are Correlated with Short-Term Postoperative Complications (위암 환자에서 수술 전후의 영양지표의 변화와 수술 후 단기간 합병증과의 연관성)

  • Oh, Cheong-Ah;Kim, Dae-Hoon;Oh, Seung-Jong;Choi, Min-Gew;Noh, Jae-Hyung;Sohn, Tae-Sung;Kim, Sung;Bae, Jae-Moon
    • Journal of Gastric Cancer
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    • v.10 no.1
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    • pp.5-12
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    • 2010
  • Purpose: The aim of this study was to evaluate the preoperative and postoperative nutritional statuses of patients with gastric cancer and to investigate the nutritional factors that are correlated with perioperative complications. Materials and Methods: From January 2008 to Jun 2008, 669 patients who underwent curative gastrectomy were enrolled in a retrospective study. To evaluate the changes of their nutritional status preoperatively and postoperatively, we measured the total lymphocyte count, the serum albumin, the body weight change and the BMI. The nutritional factors correlated with short-term postoperative complications were analyzed. Results: The total lymphocyte count and serum albumin decreased from the first preoperative day to the $5^{th}$ day after operation, but they tended to increase and approach the normal range 6 months after operation. The only factor correlated with the short-term postoperative complications (defined as the ones that occurred for 30 days) was the serum albumin checked on the $5^{th}$ day after operation. Conclusion: Low serum albumin on the $5^{th}$ day after operation was correlated with postoperative short-term complications. Serum albumin can be the preoperative statistical parameter that can predict the occurrence of postoperative complications.

Effects of β3-Adrenergic Receptor Polymorphism on the Hyperglycemia in Korean Subjects (베타 3-아드레날린 수용체의 유전자형이 고혈당증 유발에 미치는 영향)

  • 오현희;최선미;양현성;김길수;윤유식
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.1
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    • pp.83-90
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    • 2004
  • This study was conducted to examine the effects of $\beta$3-adrenergic receptor polymorphism on the blood glucose level and obesity in 530 volunteers, who attended a weight loss program in a local obesity clinic. The age differences in total subjects and the distribution of male and female were 26.55$\pm$0.31 yr, 9.1% (n=48), 90.9% (n=492). The genotype distribution of $\beta$3-AR gene polymorphism were WW type 75%, WR type 22% and RR type 3%. Among many parameters, fasting blood glucose was significantly higher in WR+RR type (p=0.001) compared with WW type. When the subjects were divided into two groups by 6.105 mmol/L of the fasting blood glucose level, the frequency of hyperglycemia was 23.3% in WW type subjects, while there was a increase to 35.6% in WR+RR type subjects (p=0.011, $\chi$$^2$-analysis). When hyperglycemia group was compared with normoglycemia group, obesity index (p=0.044), %body fat (p=0.046) and TG (p=0.000) were significantly higher, and HDL (p=0.006) was significantly lower in the hyperglycemia. When all of the above factors were included in stepwise logistic regression analysis to find risk factors of hyperglycemia, the results were that the odds ratio for hyperglycemia were 2.015 (p=0.011) for WR+RR type of $\beta$3-AR gene, 2.165 (p=0.000) for TG and 0.419 (p=0.059) for HDL cholesterol. There was a significantly positive correlation between the blood glucose vs BMI, WHR, body fat in the WW type (r=0.099, 0.119, 0.082) However, in the WR and RR type there were no significance between the blood glucose vs BMI, WHR, body fat. These data suggest that the WR+RR genotype of $\beta$3-AR has a very strong association with increased blood glucose level and might be a significant risk factor for hyperglycemia among Korean subjects.

Oxide perovskite crystals type ABCO4:application and growth

  • Pajaczkowska, A.
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1996.06a
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    • pp.258-292
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    • 1996
  • In the last year great interest appears to YBCO thin films preparation on different substrate materials. Preparation of epitaxial film is a very difficult problem. There are many requirements to substrate materials that must be fullfilled. Main problems are lattice mismatch (misfit) and similarity of structure. From paper [1] or follows that difference in interatomic distances and angles of substrate and film is mire important problem than similarity of structure. In this work we present interatomic distances and angle relations between substrate materials belonging to ABCO4 group (where A-Sr or Ca, B-rare earth element, C-Al or Ga) of different orientations and YBCO thin films. There are many materials used as substrates for HTsC thin films. ABCO4 group of compounds is characterized by small dielectric constants (it is necessary for microwave applications of HTsC films), absence of twins and small misfit [2]. There most interesting compounds CaNdAlO4, SrLaAlO4 and SrLaGaO4 were investigated. All these compounds are of pseudo-perovskite structure with space group 14/mmm. This structure is very similar to structure of YBCO. SLG substrate has the lowest misfit (0.3%) and dielectric constant. For preparation of then films of substrates of this group of compound plane of <100> orientation are mainly used. Good quality films of <001> orientations are obtained [3]. In this case not only a-a misfit play role, but c-3b misfit is very important too. Sometimes, for preparation of thin films substrates of <001> and <110> orientations were manufactured [3]. Different misfits for different YBCO faces have been analyzed. It has been found that the mismatching factor for (100) face is very similar to that for (001) face so there is possibility of preparation of thin films on both orientations. SrLaAlO4(SLA) and SrLaGaO4(SLG) crystals of general formula ABCO4 have been grown by the Czochralski method. The quality of SLA and SLG crystals strongly depends on axial gradient of temperature and growth and rotation rates. High quality crystals were obtained at axial gradient of temperature near crystal-melt interface lower than 50℃/cm, growth rate 1-3 mm/h and the rotation rate changing from 10-20pm[4]. Strong anisotropy in morphology of SLA and SLG single crystals grown by the Czochralski method is clearly visible. On the basics of our considerations for ABCO4 type of the tetragonal crystals there can appear {001}, {101}, and {110} faces for ionic type model [5]. Morphology of these crystals depend on ionic-covalent character of bonding and crystal growth parameters. Point defects are observed in crystals and they are reflected in color changes (colorless, yellow, green). Point defects are detected in directions perpendicular to oxide planes and are connected with instability of oxygen position in lattice. To investigate facets formations crystals were doped with Cr3+, Er3+, Pr3+, Ba2+. Chromium greater size ion which is substituted for Al3+ clearly induces faceting. There appear easy {110} faces and SLA crystals crack even then the amount of Cr is below 0.3at.% SLG single crystals are not so sensitive to the content of chromium ions. It was also found that if {110} face appears at the beginning of growth process the crystal changes its color on the plane {110} but it happens only on the shoulder part. The projection of {110} face has a great amount of oxygen positions which can be easy defected. Pure and doped SLA and SLG crystals measured by EPR in the<110> direction show more intensive lines than in other directions which allows to suggest that the amount of oxygen defects on the {110} plane is higher. In order to find the origin of colors and their relation with the crystal stability, a set of SLA and SLG crystals were investigated using optical spectroscopy. The colored samples exhibit an absorption band stretching from the UV absorption edge of the crystal, from about 240 nm to about 550 m. In the case of colorless sample, the absorption spectrum consists of a relatively weak band in the UV region. The spectral position and intensities of absorption bands of SLA are typical for imperfection similar to color centers which may be created in most of oxide crystals by UV and X-radiation. It is pointed out that crystal growth process of polycomponent oxide crystals by Czochralski method depends on the preparation of melt and its stoichiometry, orientation of seed, gradient of temperature at crystal-melt interface, parameters of growth (rotation and pulling rate) and control of red-ox atmosphere during seeding and growth (rotation and pulling rate) and control of red-ox atmosphere during seeding and growth. Growth parameters have an influence on the morphology of crystal-melt interface, type and concentration of defects.

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Change of Dose Exposure and Improvement of Image Quality by Additional Filtration in Mammography (유방촬영용장치 부가필터에 따른 선량변화 및 화질개선)

  • Cho, Woo Il;Kim, Young Kuen;Lee, Gil Dong
    • Journal of Radiation Protection and Research
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    • v.38 no.2
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    • pp.78-90
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    • 2013
  • Recently, the interest on exposure to radiation is rising. The radiation exposure of mammography is higher in absorbed dose than of X-ray, therefore unnecessary exposure needs to be reduced, and higher image quality is needed. Generally, ray quality of the radiation imaging is an important factor that determines image quality and the amount of ray exposure, and they are affected by tube voltage and added filter. The X-ray energy that is exposed from mammography device is generally a continuous spectrum, which includes low energy that has minute influence on the image quality, and high energy that hinders contrast on image. Currently, molybdenum (Mo) and rhodium (Rh) are the most used added filters for mammography device, and they are used differently according to the energy region of X-ray. This study aims to find out the degree of reduction in exposure dose according to the thickness of aluminum (Al), and to study the changes in image quality and dose when the added filter plates that are made with niobium (Nb) or zirconium (Zr) are used, other than molybdenum (Mo) and rhodium (Rh), the two most used added filters that have similar atomic number and K-absorption regions as Nb and Zr. In this study, single-added filters of molybdenum (Mo), niobium (Nb), and zirconium (Zr) are used, and in some cases, Aluminum (Al) is combined with the single filters. In this case, image quality is considered to be improved depending on the type of added filters, and by using Aluminum (Al) filter together with the others, unnecessary X-ray of low energy would be absorbed, therefore the dose is expected to decrease without any influence when the concentration level becomes identical.