• Title/Summary/Keyword: 수치적 방법

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Survey of Caffeine levels in the Favorite Diets of Children (어린이 기호식품 중 카페인 함량에 대한 조사)

  • Lee, E-Na;Kim, Hee-Jin;Im, Ji-Young;Kim, Jeoung-A;Park, Hye-Young;Ryu, Ju-Young;Ko, Kwang-Rack;Kim, Hyung-Sik
    • Journal of Food Hygiene and Safety
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    • v.22 no.3
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    • pp.173-178
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    • 2007
  • Children may respond differently to the caffeine from adults because they have different physiologic makeup and are functionally immature in terms of hepatic and renal function; this leads to the slower clearance of caffeine in early life. Therefore, children are often assumed to be more susceptible to caffeine effects. Alarge number of food supplements may interfere with these processes, and therefore caffeine exposure may have more serious consequences for children than for adults, irrespective of sensitivity. However, there has never been a national dietary survey on caffeine intakes in children. The purpose of our study was to identify caffeine intakes and beverage sources of caffeine in a representative sample of children in Busan, Korea. Caffeine intakes were based only on beverages included in the Continuing Surveys of Food Intakes by individuals. The caffeine content of the beverages ranged from 2.8 to 65.2mg/100ml for cola, soft drinks, and teas. Caffeine was not completely absent from caffeine-free colas, juice, and milk. In this study, cola-type beverages were an important dietary source of caffeine in the children. Daily caffeine intake for children was estimated to range from 12.5 to 250 mg/day. In general, the acceptable daily intake (ADI) of caffeine should cover the entire population including children. Therefore, special considerations should be needed regarding the consumption of soft drinks containing caffeine to children below the 12 years of age.

Implementation of Markerless Augmented Reality with Deformable Object Simulation (변형물체 시뮬레이션을 활용한 비 마커기반 증강현실 시스템 구현)

  • Sung, Nak-Jun;Choi, Yoo-Joo;Hong, Min
    • Journal of Internet Computing and Services
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    • v.17 no.4
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    • pp.35-42
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    • 2016
  • Recently many researches have been focused on the use of the markerless augmented reality system using face, foot, and hand of user's body to alleviate many disadvantages of the marker based augmented reality system. In addition, most existing augmented reality systems have been utilized rigid objects since they just desire to insert and to basic interaction with virtual object in the augmented reality system. In this paper, unlike restricted marker based augmented reality system with rigid objects that is based in display, we designed and implemented the markerless augmented reality system using deformable objects to apply various fields for interactive situations with a user. Generally, deformable objects can be implemented with mass-spring modeling and the finite element modeling. Mass-spring model can provide a real time simulation and finite element model can achieve more accurate simulation result in physical and mathematical view. In this paper, the proposed markerless augmented reality system utilize the mass-spring model using tetraheadron structure to provide real-time simulation result. To provide plausible simulated interaction result with deformable objects, the proposed method detects and tracks users hand with Kinect SDK and calculates the external force which is applied to the object on hand based on the position change of hand. Based on these force, 4th order Runge-Kutta Integration is applied to compute the next position of the deformable object. In addition, to prevent the generation of excessive external force by hand movement that can provide the natural behavior of deformable object, we set up the threshold value and applied this value when the hand movement is over this threshold. Each experimental test has been repeated 5 times and we analyzed the experimental result based on the computational cost of simulation. We believe that the proposed markerless augmented reality system with deformable objects can overcome the weakness of traditional marker based augmented reality system with rigid object that are not suitable to apply to other various fields including healthcare and education area.

Clinical Characteristics and Renal Outcomes of Acute Focal Bacterial Nephritis in Children (소아 급성 세균성 신엽염의 임상상 및 신장 예후)

  • Lee Dong-Ki;Kwon Duck-Geun;Lim Yun-Ju;Shin Yun-Hye;Yun Suk-Nam;Pai Ki-Soo
    • Childhood Kidney Diseases
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    • v.8 no.2
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    • pp.229-238
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    • 2004
  • Purpose: This study was perfonned to elucidate the clinical pictures of acute focal bacterial nephritis(nephronia) in children. Methods: We reviewed 9 children with nephronia diagnosed by ultrasonography or computed tomography of kidneys from September 1994 to August 2004. Results: The overall male to female ratio was 2:1, and the age distribution ranged from 0.1 to 6 years(mean $2.8{\pm}2.2$). The cardinal symptoms were fever, chills, abdominal pain and dysuria/frequency. The initial leukocyte count was $21,000{\pm}5,600/uL$, ESR $60{\pm}23mm/hr$, CRP $17{\pm}10\;mg/dl$. Pyuria was noted in every patient and persisted for $10.5{\pm}7.8$ days after antimicrobial treatment. Abdominal sonography demonstrated focal lesion of ill-defined margin and low echogenicity in 5 of 9 patients(55.6%), while computed tomography revealed nonenhancing low density area in all patients(100%). Three of 9 patients(33.3%) had vesicoureteral reflux, greater than grade III. The initial $^{99m}Tc-DMSA$ scan showed one or multiple cortical defects in every patient, and improvements were noted in 2(33.3%) of 6 patients who received follow up scan after 4 months. Intravenous antibiotics was given in every patient under admission. Total febrile period was $11.8{\pm}6.3$ days(pre-admission, $4.0{\pm}3.0;$ post-admission, $7.8{\pm}5.5$ days) and the patients needed hospitalization for $17.2{\pm}8.1$ days. Conclusion: For the early diagnosis of 'acute focal bacterial nephritis' we should perform renal computed tomography first rather than ultrasonography, when the child has toxic symptoms and severe inflammatory responses in blood and urine.

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Comparative Analysis of $\alpha$-STAT and pH-STAT Strategies During Deep Hypothermic Circulatory Arrest in the Young Pig (초저체온 순환정지시 $\alpha$-STAT와 pH-STAT 조절법의 비교분석 -어린돼지를 이용한 실험모델에서-)

  • Kim, Won-Gon;Lim, Cheong;Moon, Hyun-Jong;Won, Tae-Hee;Kim, Yong-Jin
    • Journal of Chest Surgery
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    • v.31 no.6
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    • pp.553-559
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    • 1998
  • Introduction: The most dramatic application of hypothermia in cardiac surgery is in deep hypothermic circulatory arrest(DHCA). Because man in natural circumstances is never exposed to this extreme hypothermic condition, one of the controversial aspects of clinical hypothermia is appropriate acid-base management($\alpha$-stat versus pH-stat). This study aims to compare $\alpha$-stat with pH-stat for: (1) brain cooling and re-warming speed during hypothermia induction and re-warming by cardiopulmonary bypass (CPB); (2) cerebral perfusion, metabolism, and their coupling; and (3) the extent of development of cerebral edema after circulatory arrest, in young pigs. Materials & Methods: Fourteen young pigs were assigned to one of two strategies of gas manipulation. Cerebral blood flow was measured with a cerebral venous outflow technique. After a median sternotomy, CPB was established. Core cooling was initiated and continued until nasopHaryngeal temperature fell below $20^{\circ}C$. The flow rate was set at 2,500 ml/min. Once their temperatures were below $20^{\circ}C$, the animals were subjected to DHCA for 40 mins. During cooling, acid-base balance was maintained according to either $\alpha$-STAT or pH-STAT strategies. After DHCA, the body was re-warmed to normal body temperature. The animals were then sacrificed, and their brains measured for edema. Cerebral perfusion and metabolism were measured before the onset of CPB, before cooling, before DHCA, 15 mins after re-warming, and upon completion of re-warming. Results & Conclusion: Cooling time was significantly shorter with $\alpha$-stat than with pH-stat strategy, while there were no significant differences in rewarming time between the two groups. Nosignificant differences were found in cerebral blood flow, metabolic rate, or flow/ metabolic rate ratio between two groups. Temperature-related differences were significant in cerebral blood flow, metabolic rate, and flow/metabolic rate ratio within each group. Brain water content showed no significant differences between two groups.

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Increased Incidence of Endometrial Polyps in Women with Endometriosis; the Association with Severity (자궁내막증 여성에서 증가된 자궁내막용종의 빈도; 질환의 중증도와의 관련성)

  • Chang, Hye Jin;Hwang, Kyung Joo;Kim, Mi Ran;Ahn, Sang Tae;Byun, Jae Guang;Lee, Eun Hee;Park, Jin Young
    • Clinical and Experimental Reproductive Medicine
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    • v.33 no.3
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    • pp.199-205
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    • 2006
  • Objective: The aim of this study was to evaluate the correlation between severity of endometriosis and the incidence of endometrial polyp. Methods: The study population consisted of six hundred thirty-one women who had undergone laparoscopic operation due to infertility, severe dysmenorrhea or ovarian tumors. We divided two groups: 434 women with endometriosis (study group) and 197 women without the disease (control group). The presence of endometriosis was documented by diagnostic or therapeutic laparoscopic operation and the disease severity was scored according to revised The American Fertility Society classification. We confirmed the endometrial polyps by pathologic examination after hysteroscopic polypectomy, and compared endometrial polyp incidence according to severity of endometriosis. Results: There was no significant difference between groups with regard to age, mean duration of infertility. Endometrial polyps were found in 274 women (63.0%) with endometriosis and in 58 controls (29.8%, p=0.0000). The incidence of endometrial polyps differed significantly according to stage of endometriosis. The incidence of endometrial polyps were 77/142 (54.2%), 58/90 (64.4%), 73/108 (67.6%, p<0.05), 66/94 (70.2%, p<0.05) in endometriosis stage I, II, III, and IV. There was a linear correlation between stage of endometriosis and endometrial polyps incidence (p=0.008). Conclusion: Endometriosis is accompanied by endometrial polyps. This results showed positive correlation between severity of the endometriosis and incidence of endometrial polyps. It is the possible mechanism for low pregnancy rate in the severe endometriosis.

The Clinical Study on the Neonate Delivered Under the Condition of the Maternal Smoking and Alcohol in Pregnancy (재태기간 중 산모의 음주와 흡연에 노출된 신생아의 임상적 고찰)

  • Kong, Sun Hui;Kim, Soo Yeon;Lee, Ho Jun;Kim, Hak Sung;Lee, Dong Woo;Kim, Jae Yoon
    • Clinical and Experimental Pediatrics
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    • v.48 no.1
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    • pp.34-39
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    • 2005
  • Purpose : Perinatal complications associated with maternal smoking and alcohol ingestion in pregnancy have been well documented. But until now there has been no clinical data on it collected in our country. In this paper, we tried to research the association between maternal smoking and alcohol ingestion in pregnancy and the physical indices of the neonate at delivery among unmaried mothers from one charitable institution. Methods : We enlisted 125 unmarried with a history of smoking and alcohol consumption during pregnancy who delivered a baby in National Medical Center from March, 2001 to March, 2004 as a study group. As a control, 174 unmarried mothers without a history of smoking and alcohol were enlisted. Then, we compared the physical indices - birth weight, height, and the head circumference - of the neonates from both groups. Furthermore, we investigated the effects of the period and the quantity of maternal smoking and alcohol ingestion on the physical indices of the neonates from the both groups. Results : Low physical indices of neonates were found in the study group(either smoking group, or drinking group) compared with the control group. The quantity of smoking or drinking and the period of smoking or drinking have no significant effect on physical indices. Conclusion : We found that maternal smoking and alcohol result in the low physical index of neonates, and educational initiatives must be directed at expectant mothers to emphasize the harmful effects of smoking and alcohol ingestion in pregnancy.

The Study of Error for Analysis in Dynamic Image from the Error of Count Rates in NaI (Tl) Scintillation Camera (NaI (Tl) 신틸레이션 카메라에서 계수율 오차에 따른 동적 영상 분석치 산출 오류에 관한 연구)

  • Oh, Joo-Young;Kang, Chun-Goo;Kim, Jung-Yul;Park, Hoon-Hee;Oh, Ki-Baek;Kim, Jae-Sam
    • Journal of radiological science and technology
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    • v.36 no.4
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    • pp.291-297
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    • 2013
  • This study is aimed to evaluate the effect of $T_{1/2}$ upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with $^{99m}TcO_4^-$ of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in $x^2$ test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of $T_{1/2}$ error from change of gradient with -0.25% to +0.25%, if $T_{1/2}$ is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see $T_{1/2}$ error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a tendency that count rate changes over time at this study, and we proved that it can effect $T_{1/2}$. And also, there is need of appropriate phantoms and the method of quality management like this study, because there are not any advice or limitation degrees for domestic medical purpose scintillation camera.

Effect of Pulsatile Versus Nonpulsatile Blood Flow on Renal Tissue Perfusion in Extracorporeal Circulation (체외순환에서 박동 혈류와 비박동 혈류가 신장의 조직관류에 미치는 영향)

  • Kim Hyun Koo;Son Ho Sung;Fang Yang Hu;Park Sung Young;Kim Kwang Taik;Kim Hark Jei;Sun Kyung
    • Journal of Chest Surgery
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    • v.38 no.1 s.246
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    • pp.13-22
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    • 2005
  • It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

Evaluation on the Accuracy of the PPS in the Proton Therapy System, Which Uses the Self Made QA Phantom (자체 제작한 QA Phantom을 이용한 양성자 PPS (Patient Positioning System)의 정확성 평가)

  • Lee, Ji-Eun;Kim, Jae-Won;Kang, Dong-Yoon;Choi, Jae-Hyeok;Yeom, Du-Seok
    • The Journal of Korean Society for Radiation Therapy
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    • v.24 no.2
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    • pp.115-121
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    • 2012
  • Purpose: The process of the proton treatment is done by comparing the DRR and DIPS anatomic structure to find the correction factor and use the PPS to use this factor in the treatment. For the accuracy of the patient set up, the PPS uses a 6 axis system to move. Therefore, there needs to be an evaluation for the accuracy between the PPS moving materialization and DIPS correction factor. In order to do this, we will use a self made PPS QA Phantom to measure the accuracy of the PPS. Materials and Methods: We set up a PPS QA Phantom at the center to which a lead marker is attached, which will act instead of the patient anatomic structure. We will use random values to create the 6 axis motions and move the PPS QA Phantom. Then we attain a DIPS image and compare with the DRR image in order to evaluate the accuracy of the correction factor. Results: The average correction factor, after moving the PPS QA Phantom's X, Y, Z axis coordinates together from 1~5 cm, 1 cm at a time, and coming back to the center, are 0.04 cm, 0.026 cm, 0.022 cm, $0.22^{\circ}$, $0.24^{\circ}$, $0^{\circ}$ on the PPS 6 axis. The average correction rate when moving the 6way movement coordinates all from 1 to 2 were 0.06 cm, 0.01 cm, 0.02 cm, $0.1^{\circ}$, $0.3^{\circ}$, $0^{\circ}$ when moved 1 and 0.02 cm, 0.04 cm, 0.01 cm, $0.3^{\circ}$, $0.5^{\circ}$, $0^{\circ}$ when moved 2. Conclusion: After evaluating the correction rates when they come back to the center, we could tell that the Lateral, Longitudinal, Vertical were all in the acceptable scope of 0.5 cm and Rotation, Pitch, Roll were all in the acceptable scope of $1^{\circ}$. Still, for a more accurate proton therapy treatment, we must try to further enhance the image of the DIPS matching system, and exercise regular QA on the equipment to reduce the current rate of mechanical errors.

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Binocular Vision Corrective Spectacle Lenses Reduce Visual Fatigue in 3-D Television Viewing (양안시 교정안경의 3차원 텔레비전 시청 중 발생한 안정피로 감소)

  • Yoon, Jeong Ho;Kim, Jae-Do
    • Journal of Korean Ophthalmic Optics Society
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    • v.19 no.3
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    • pp.363-369
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    • 2014
  • Purpose: Three-dimensional (3D) displays are very useful in many fields, but induce physical discomforts in some people. This study is to assess symptom type and severity of asthenopia with their habitual distance corrective spectacle (HDCS) and their binocular vision corrective spectacle lenses (BVCSL) in people who feel physical discomforts. Methods: 35 adult subjects (ages $32.2{\pm}4.4$ yrs) were pre-screened out of 98 individuals to have the highest symptom/asthenopia scores following 65 minutes of 3D television viewing with HDCS. These 35 individuals were then retested symptom/asthenopia scores during they watched 3D television for 65 minutes at a distance of 2.7 m with wearing BVCSL of horizontal, vertical or base down yoked prisms. A 4-point symptom-rating scale questionnaire (0=no symptom and 3=severe) was used to assess 11 symptoms (e.g., blur, diplopia, etc.) related to visual fatigue/visual discomfort. Distance and near lateral phoria were measured using Howell phoria card and vertical phoria were measured using Maddox rod. Symptoms induced by watching 3D TV were compared between wearing HDCS and BVCSL. Results: Asthenopia in watching 3D TV with wearing BVCS was significantly lower than wearing HDCS at 5, 25, 45, and 65 minutes (all p < 0.001, paired t-tests). In only refractive error power correction power group, all asthenopia was not significantly different between HDCS and BVCSL (all $p{\geq}0.05$, paired t-tests). In prism correction groups for binocular imbalance, symptoms of asthenopia, however, was significantly lower for when wearing BVCSL than when wearing HDCS (all p < 0.05). Conclusions: Correction of phoria/vergence-based binocular vision imbalance can reduce asthenopia during 3D television viewing. An individual with binocular vision imbalance need corrected/compensated glasses with appropriate prisms prior to prolonged viewing of 3D television displays to reduce asthenopia/visual fatigue.