• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.13-23
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• 2003

Backgrounds: The present study in angulated coronary stenosis was to evaluate the influence of velocity and wall shear stress (WSS) on coronary atherosclerosis, the changes of hemodynamic indices following coronary stenting, as well as their effect of evolving in-stent restenosis using human in vivo hemodynamic parameters and computed simulation quantitatively and qualitatively. Methods: Initial and follow-up coronary angiographies in the patients with angulated coronary stenosis were performed (n=80). Optimal coronary stenting in angulated coronary stenosis had two models: < 50 % angle changed(model 1, n=43), > 50% angle changed group (model 2, n=37) according to percent change of vascular angle between pre- and post-intracoronary stenting. Flow-velocity wave obtained from in vivo intracoronary Doppler study data was used for in vitro numerical simulation. Spatial and temporal patterns of velocity vector and recirculation area were drawn throughout the selected segment of coronary models. WSS of pre/post-intracoronary stenting were calculated from three-dimensional computer simulation. Results: Follow-up coronary angiogram demonstrated significant difference in the percent of diameter stenosis between two groups (group 1: $40.3{\pm}30.2$ vs. group 2: $25.5{\pm}22.5%$, p<0.05). Negative WSS area on 3D simulation, which is consistent with re-circulation area of velocity vector, was noted on the inner wall of post-stenotic area before stenting. The negative WSS was disappeared after stenting. High spatial and temporal WSS before stenting fell into within physiologic WSS after stenting. This finding was prominent in Model 2 (p<0.01) Conclusions: The present study suggests that hemodynamic forces exerted by pulsatile coronary circulation termed as WSS might affect on the evolution of atherosclerosis within the angulated vascular curvature. Moreover, geometric change, such as angular difference between pre / post-intracoronary stenting might give proper information of optimal hemodynamic charateristics for vascular repair after stenting.

• Asian-Australasian Journal of Animal Sciences
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• 제22권4호
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• pp.542-549
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• 2009

An in vitro study was conducted to determine the effect of nitrate-nitrogen used as a sole dietary nitrogen source on ruminal fermentation characteristics and microbial nitrogen (MN) synthesis. Three treatment diets were formulated with different nitrogen sources to contain 13% CP and termed i) nitrate-N diet (NND), ii) urea-N diet (UND), used as negative control, and iii) tryptone-N diet (TND), used as positive control. The results of 24-h incubations showed that nitrate-N disappeared to background concentrations and was not detectable in microbial cells. The NND treatment decreased net $CH_4$ production, but also decreased net $CO_2$ production and increased net $H_2$ production. Total VFA concentration was lower (p<0.05) for NND than TND. Suppression of $CO_2$ production and total VFA concentration may be linked to increased concentration of $H_2$. The MN synthesis was greater (p<0.001) for NND than UND or TND (5.74 vs. 3.31 or 3.34 mg/40 ml, respectively). Nitrate addition diminished methane production as expected, but also increased MN synthesis.

• Radiation Oncology Journal
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• 제20권2호
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• pp.155-164
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• 2002

목적 : Ginkgo biloba extract (GBE)는 혈액순환개선효과가 있어 기존의 방사선민감제와 달리 혈류저항이 높은 악성종양에서 저산소세포 분획을 줄일 수 있으나 아직까지는 실제 임상에서 사용되는 저선량 분할 방사선조사시에도 GBE가 방사선조사 효과의 증대를 나타내는지 밝혀지지 않았다. 이에 본 연구에서는 저선량 분할 방사선조사시 GBE가 방사선조사효과증대를 나타내는지, 또한 정상조직과 악성종양의 혈류량 분포에 어떠한 영향을 미치는지 알아보고자 하였다. 대상 및 방법 : 통상적인 범위의 저산소세포 분획을 가진 C3H 마우스의 섬유육종(FSall)을 마우스 우측하지에 이식한 후 종양직경이 7 mm에 도달하였을 때 마우스 체중 kg당 100 mg의 GBE를 방사선조사 25시간 전과 매회 1시간 전에 복강내 투여 후 방사선을 조사하였다. 3 Gy 내지 12 Gy의 방사선을 일회 조사시 GBE투여군과 방사선단독조사군의 종양성장지연기간을 비교하여 GBE에 의한 방사선효과 증강율을 구하였다. 3 Gy씩 10회의 분할 방사선조사시 방사선 단독조사군의 방사선량-종양성장지연기간(tumor growth delay, TGD)의 관계식을 구하여 두 실험군의 선형회귀직선 기울기의 비율, 즉 GBE에 의한 방사선효과 증강율을 구하였다. 같은 종양을 이용하여 레이저 도플러 혈류측정기로 정상근육과 종양의 혈류량을 측정함으로써 저혈류 분포의 차이가 존재하는지 확인하였고, GBE 투여에 의한 혈류량분포의 변화 여부를 관찰하였다. 결과 : 3 Gy 내지 12 Gy의 방사선을 일회 조사시 GBE투여군의 종양성장지연기간이 방사선단독조사군에 비하여 의미있게 증가되었으며(p<0.05), GBE에 의한 방사선효과 증강율은 3일 종양성장지연 기준으로 1.16이었다. 3 Gy씩 10회의 분할 방사선조사시 방사선 단독조사군의 방사선량-종양성장지연기간(tumor growth delay, TGD)의 관계는 TGD $(days)=0.26{\times}D$ (Gy)+0.13, GBE 병용군의 경우 TGD $(days)=0.30{\times}D$ (Gy)+0.13이었고 두 실험군의 직선 기울기의 비율, 즉 GBE에 의한 방사선효과 증강율은 1.19 ($95\%$ 신뢰구간: $1.13\~1.27$)로 나타났다. 같은 종양을 이용하여 레이저 도플러 혈류측정기로 혈류량을 측정한 결과, 혈류량의 분포는 모두 Poisson 분포와 비슷한 양상을 보였다. 정상근육의 혈류량은 평균 10.15 mL/100 g/min, 종양의 혈류량은 평균 7.78 mL/100 g/min으로 종양의 평균 혈류량이 근육에 비하여 낮게 나타났고(p=0.001), 2 mL/100 g/min 이하의 저혈류 분포는 정상근육에 비하여 종양에서 높게 나타났다($0.5\%$ 대 $5.2\%$, p=0.005). 정상근육에서는 GBE 투여에 의하여 혈류량 분포에 큰 변화가 없었던 반면, 종양에서는 2 mL/100 g/min 이하의 저혈류량 분포가 감소하였고, 평균 혈류량은 $23.5\%$ 증가되었다(p=0.0004). 결론 : GBE는 방사선 일회 조사시 뿐만 아니라 분할조사시에도 방사선치료의 효과를 유의하게 증가시켰다. 또한 정상근육에 비하여 종양의 혈류량을 선택적으로 증가시킴이 확인되었다.

• 대한핵의학회지
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• 제34권3호
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• pp.252-259
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• 2000

목적: 핵의학과에서 흔하게 이용되는 Tc-99m MDP 또는 Tc-99m DTPA를 주사한 후 방사선 적응반응이 일어나는지를 확인하고, 어느 경우에 방사선 적응반응이 더 현저하게 유도되는지 알아보기 위하여 이 연구를 시행하였다. 대상 및 방법: Tc-99m MDP 또는 Tc-99m DTPA 신티그라피를 시행한 45명의 환자(남자 25명, 여자 20명, 평균 연령 $44{\pm}18$세)를 대상으로 Tc-99m MDP 뜨는 Tc-99m DTPA 주사 전과 주사 후 4시간에 각각 5 ml씩 채혈하여 배양하고 배양 46시간 후에 Cs-137조사기 (central dose rate=654 Gy/h, Gammacell 3000 Elan, Nordion, Canada)를 이용하여 2 Gy의 감마선을 조사하였다. 대조군 20명(남자 12명, 여자 8명, 평균연령 $43{\pm}7$세)의 혈액을 채혈하여 Tc-99m MDP 또는 Tc-99m DTPA 주사 전에 채혈한 군과 같은 방법으로 조사하고 배양하였다. Colcemid 처리 2시간 후에 수확하여 불안정 염색체인 반지형과 이중 중심체형 염색체의 수자를 계수 하여 불안정 염색체 출현빈도(Ydr)를 구하여 비교하였다. 고선량의 방사선 단독조사에 의한 Ydr값과 방사성의약품 투여 후 고선량의 방사선 조사에 의해 유도된 Ydr값의 차이값을 적응반응지수로 정의하고, Tc-99m MDP 신티그라피와 Tc-99m DTPA 신티그라피의 적응반응지수를 비교하였다. 결과. 2 Gy 단독조사에 의한 Ydr값에 비해 Tc-99m MDP 또는 Tc-99m DTPA 주사한 후에 2 Gy 조사한 군에서 Ydr값이 유의하게 감소하였다($0.45{\pm}0.20\;vs.\;0.24{\pm}0.10$, p=0.001). Tc-99m MDP 또는 Tc-99m DTPA에 의해 유도된 적응반응은 단백합성억제제인 cycloheximide에 의해 억제되었다($0.24{\pm}0.10\;vs.\;0.43{\pm}0.16$, p=0.001). Tc-99m MDP 신티그라피에 의한 적응반응 지수는 Tc-99m DTPA 신티그라피에 의한 적응반응지수에 비해 유의하게 높았다($0.10{\pm}0.06\;vs.\;0.24{\pm}0.05$, p=0.0001). 결론: Tc-99m MDP 신티그라피 또는 Tc-99m DTPA 신티그라피에 의한 저선량의 방사선 조사에 의하여 말초혈액 림프구에서 방사선 적응반응이 유도되었고, 적응반응의 정도는 Tc-99m MDP 골 신티그라피를 시행하는 환자에서 더욱 현저함을 알 수 있었다.

• Journal of Gastric Cancer
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• 제20권3호
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• pp.313-327
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• 2020

Purpose: Nodal downstaging after preoperative therapy for gastric cancer has been shown to impart excellent prognosis, but this has not been validated in a national cohort. The role of neoadjuvant chemoradiation (NACR) in nodal downstaging remains unclear when compared with that of neoadjuvant chemotherapy alone (NAC). Furthermore, it is unknown whether the prognostic implications of nodal downstaging differ by preoperative regimen. Materials and Methods: Using the National Cancer Database, overall survival (OS) duration was compared among natural N0 (cN0/ypN0), downstaged N0 (cN+/ypN0), and nodepositive (ypN+) gastric cancer patients treated with NACR or NAC. Factors associated with nodal downstaging were examined in a propensity score-matched cohort of cN+ patients, matched 1:1 by receipt of NACR or NAC. Results: Of 7,426 patients (natural N0 [n=1,858, 25.4%], downstaged N0 [n=1,813, 24.4%], node-positive [n=3,755, 50.4%]), 58.2% received NACR, and 41.9% received NAC. The median OS durations of downstaged N0 (5.1 years) and natural N0 (5.6 years) patients were similar to one another and longer than that of node-positive patients (2.1 years) (P<0.001). In the matched cohort of cN+ patients, more recent diagnosis (2010-2015 vs. 2004-2009) (odds ratio [OR], 2.57; P<0.001) and NACR (OR, 2.02; P<0.001) were independently associated with nodal downstaging. The 5-year OS rate of downstaged N0 patients was significantly lower after NACR (46.4%) than after NAC (57.7%) (P=0.003). Conclusions: Downstaged N0 patients have the same prognosis as natural N0 patients. Nodal downstaging occurred more frequently after NACR; however, the survival benefit of nodal downstaging after NACR may be less than that when such is achieved by NAC.

• 대한환경공학회지
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• 제38권5호
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• pp.228-235
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• 2016

아질산화 반응을 통한 nitrite 축적은 단축질소제거 혹은 anammox 공정 수립을 위해 필수적이고 이 반응의 속도가 전체 질소제거공정의 효율에 큰 영향을 미칠 수 있다. 본 연구는 부유 미생물 연속류 반응기에서 pH 농도가 암모니아 폐수(2,000 mgN/L) 처리에 주는 복잡하고 다양한 영향 들을 modeling과 실험을 통해 종합적으로 분석하였다. modeling 연구 결과 반응의 안정성(stability)은 pH에 의해 지대한 영향을 받으며, free ammonia 저해가 심해지는 알칼리성 환경일수록 안정적 운전 영역(stable region)은 축소되었다. 기질과 pH의 좌표 상에서 stable region과 unstable region을 가르는 경계(stability ridge) 근처에서 안정적인 최대반응속도를 얻을 수 있고, 이 운전조건에서 아질산 축적 가능성도 최대가 되었다. stability ridge 근처의 조건에서 반응기를 운전한 결과 아질산화속도는 안정적으로 약 $6kgN/m^3-d$까지 얻을 수 있었고, 아질산축적율은 약 99% 이었다. 그러나 unstable region에서는 부하증가를 통한 반복된 교란 결과 유출수 암모니아 농도가 회복 불가능한 상태로 상승하였다. Modeling 결과 고유(intrinsic) 최적 pH 값을 고정하여도 실험에서 관찰되는 최적 운전 pH는 사용 기질의 농도가 높을수록 낮아지는 것으로 나타났으며, 이는 문헌에서 보고된 경향과 일치 하였다. 본 연구의 modeling 조건에서 95% 아질산화(5%는 암모니아로 잔존)를 위한 최적 운전 pH는 ~8.0인 것으로 예측되었으나, anammox 유입수 생산을 위해 55% 아질산화하려 할 때의 최적 운전 pH는 ~7.2로 낮아 졌다.

• 한국항해항만학회지
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• 제42권3호
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• pp.201-206
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• 2018

본 연구는 우리나라 최대 항만인 부산항의 남외항 정박지를 VTS(Vessel Traffic Service)에서 효율적으로 관리하는 방안을 제시하기 위해 정박선간 적정한 영역감시(Domain Watch)를 산정하는 데 목적이 있다. 이를 위해 영역감시 산출 방법을 제시하고 최근 정박지 이용 현황 중 정박선이 가장 많았던 기간에 선박 길이(L), 정박선간 거리($D_{ij}$), 영역감시 반경(R), 선박 길이 대비 영역감시 반경(R/L)을 1시간 간격으로 조사하였다. 조사된 자료에 대해 기술 분석을 한 결과, 정박선 한 척이 다른 정박선과 안전거리를 확보할 수 있는 최소 R/L을 조사된 전체 자료의 70 %ile(백분위수)에 해당하는 2.85를 기준으로 산정할 수 있었다. 이 결과를 부산항 남외항 정박지에 적용하여 이를 '항만 및 어항 설계 기준(2014)과 비교한 결과 상당 부분 일치하였고, 이를 통해 VTS에서 정박선의 영역감시 반경을 최소 2.85L 이상으로 설정하는 것이 타당함을 확인하였다. 본 연구는 정박지 안전 관리를 VTS 차원에서 검토한 것으로, 부산항과 같은 집단 정박지를 운영 중인 타 항만에 적용할 경우 정박지를 이용하는 선박의 안전과 VTS의 안전 관리 방안 마련에도 기여할 수 있을 것으로 기대된다.

• Radiation Oncology Journal
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• 제13권1호
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• pp.33-40
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• 1995

Purpose : To assess the efficacy and toxicity of the preoperative radiotherapy with or without chemotherapy in locally advanced rectal cancer Methods : Forty three patients (clinically diagnosed stages above or equal to Astler-Coiler stage B2 without distant metastasis) were assigned to preoperative radiotherapy alone arm (n=16) or combined preoperative radiotherapy and chemotherapy arm (n=27). Preoperative radiotherapy of 4500 cGy to whole pel-vis +/-540 cGy boost to primary site and concurrent chemotherapy of 2 cycles of 5-FU (500 mg/$m^2$) and leucovorin (20 mg/$m^2$) were used. Fifteen patients of preoperative radiotherapy alone arm and 19 of combined arm received surgical resection after preoperative treatment. Results : During the preoperative treatment, no significant complication was developed in both groups. Pathologic results were as follows; complete remission 1, Bl 1, B2 6, C1 2, C2, 5 in preoperative radiotherapy alone arm and complete remission 2, Bl 8, B2 4, C2 3, D 2 in combined arm. Postoperative complications were delayed perineal wound healing in three patients, intestinal obstruction in three patients (one managed by conservative medical treatment, two by surgical treatment). Conclusion : The combined preoperative radiotherapy and chemotherapy arm was more effective in pathological response and lymph node negativity rate than the preoperative radiotherapy alone arm. Both the preoperative radiotherapy alone arm and the combined arm were generally well tolerated and did not result in an increased postoperative morbidity.

• Asian-Australasian Journal of Animal Sciences
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• 제13권8호
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• pp.1154-1161
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• 2000

Two experiments were conducted to evaluate the efficacy of cupric citrate (Cu-citrate) relative to cupric sulfate $(CuSO_4)$ as a Cu source for weanling and grow-finish pigs. In addition, the use of liver and bile Cu concentrations as indices of the bioavailability of Cu sources was investigated. Experiment one consisted of a nursery phase (35 d; initial BW=6.4 kg, final BW=21.4 kg) followed by a grow-finish phase (103 d; initial BW=21.5 kg, final BW=111.7 kg). Experiment two only consisted of a nursery phase (35 d; initial BW=6.3 kg, final BW=18.6 kg). Dietary treatments were identical for both experiments and consisted of: control (10 ppm $CuSO_4$); control+66 or 225 ppm $CuSO_4$; control+33, 66, or 100 ppm Cu-citrate. An antibiotic was included in diets for Exp. 1 but not Exp. 2. In both experiments, growth performance variables were similar for pigs receiving Cu-citrate and $CuSO_4$; however, growth performance was not improved by high concentrations of $CuSO_4$. Liver and bile Cu were increased (p<0.05) by 225 ppm $CuSO_4$; however, lower dietary concentrations of Cu from either $CuSO_4$ or Cu-citrate did not affect the Cu concentration of liver or bile relative to that observed in the control pigs. Irrespective of Cu source, there was no linear (p>0.10) increase in plasma Cu with increasing Cu concentrations in the diet for both experiments. However, the plasma Cu concentrations were highest (p<0.10) in pigs receiving diets supplemented with 225 ppm $CuSO_4$. Sixteen randomly chosen pigs per treatment in Exp. 1 were continued through the grow-finish phase. Body weight gain and feed intake were improved (p<0.10) by 66 ppm $CuSO_4$, but other dietary Cu treatments did not alter pig performance compared to the control diet. Plasma Cu concentrations were increased (p<0.10) by 225 ppm $CuSO_4$ in the growing phase and by 225 ppm $CuSO_4$ and 100 ppm Cu-citrate in the finishing phase. These data reveal no consistent effect of $CuSO_4$ on performance; therefore, it is difficult to assess the efficacy of these two Cu sources. In addition, these studies demonstrate that liver and bile Cu are not good indicators of Cu bioavailability in pigs fed adequate to pharmacological concentrations of Cu.

• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.82-89
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• 2010

An experiment was conducted to determine the influence of dietary inorganic (copper sulfate) and organic (copper proteinate) forms of copper and energy level on performance and nutrient utilization of broiler chickens. Two hundred day-old commercial Vencobb broiler chicks were purchased and randomly distributed to 20 cages of 10 birds each. These replicates were randomly assigned to one of five treatments in a (($2{\times}2$)+1) factorial arrangement. These two factors were sources of Cu ($CuSO_{4}$ vs. Cuproteinate) and dose of Cu supplements (200 mg and 400 mg/kg dietary dry matter) and the control (no supplemental Cu). After the starter period (up to 3 weeks), from d 22 onwards another factor i.e. energy at two levels (2,900 vs. 2,920 kcal/kg diet) was introduced with the previous factorial arrangements by subdividing each replicate into two equal parts, for two energy levels, without disturbing the dose and source of Cu supplement. Cu-salt supplementation linearly increased (p<0.01) live weight (LW), live weight gain (LWG) and feed conversion ratio (FCR) at 3 weeks, whereas cumulative feed intake (CFI) was unaffected (p>0.05). LWG and FCR were higher (p<0.01) in Cu-proteinate supplemented birds compared to $CuSO_{4}$ supplementation. A linear dose response (p<0.01) of Cu was found for the performance of broiler chickens. Birds having a higher energy level in the finisher stage increased (p<0.01) LWG and FCR. Cumulative feed intake was similar (p>0.05) across the groups up to the 5th week. Cu-proteinate increased performance of broiler chickens compared to $CuSO_{4}$. Dose of supplemental Cu-salt irrespective of source showed a linear response (p<0.01) for performance. Supplementation of Cu-proteinate increased metabolizability of DM (p<0.01), NFE (p<0.05), total carbohydrate (p<0.01) and OM (p<0.01) at the starter period. Increased dose of Cu-salt linearly increased (p<0.01) metabolizability of DM, CP, CF, NFE and OM. Higher energy level in the diet improved DM (p<0.05), EE (p<0.01), NFE (p = 0.01), total carbohydrate (p<0.01) and OM (p<0.01) metabolizability. Cu-proteinate supplementation showed better nutrient utilization compared to CuSO4. Dose of Cu linearly increased DM, CP, EE, NFE, total carbohydrate and OM metabolizability. CF metabolizability was unaffected (p>0.05) among the treatments. In conclusion, dietary supplementation of Cu-salt more than the requirement may improve performance and nutrient utilization in broiler chickens even with a high energy finisher diet. Cu-proteinate showed better performance and nutrient utilization compared to $CuSO_{4}$.