실리카광물의 산침출 정제와 불순물 분석법 연구 (Impurity analysis and acid leaching purification of silica minerals)
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- 분석과학
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- 제20권6호
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- pp.516-523
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- 2007
2N급(99 %)의 실리카를 3N급(99.9 %)으로 향상시키기 위해서 널리 이용되고 있는 산 침출법(acid leaching)들의 정제효과와 실리카광물에 존재하는 불순물의 분석법에 대한 연구를 수행하였다. 산 침출법에 이용한 용액은 0.2M-oxalic acid (pH1.5, 2.5), conc-Aqua regia, 2.5 %-HCl/HF, 1 %-
Background: Oral frailty has garnered considerable interest following its identification as a risk factor for physical frailty. The Korean oral frailty diagnosis criteria have emphasized the need for extensive research on oral frailty diagnostic items and interventions. Our study performed an in-depth analysis of the tongue-palate pressure patterns in healthy community-dwelling older adults. Methods: Of the 217 older adults aged ≥60 years who visited a senior center in Wonju, 205 participants who completed tongue pressure measurement were included in the final analysis. Pressure changes over time were recorded by instructing the participants to press their tongue against the hard palate with for 7 seconds per cycle. The participants were divided into the normal and abnormal tongue pressure (NTP and ATP, respectively) groups based on whether they achieved the target tongue pressure at least once; tongue pressure patterns were compared between the groups. Furthermore, the average time taken to achieve the standard tongue pressure value was calculated for the participants in the NTP group and used to evaluate the decrease in tongue pressure in the ATP group. Results: Among the 205 participants, 40.5% had ATP. The tongue pressure graph revealed a gentle and consistent incline that was maintained even after achieving standard tongue pressure in the NTP group. The graph was more extreme in the ATP group, and the changes in the pressure type varied across individuals; the tongue pressure was only 48.4%, 40.7%, 31.9%, and 22.6% of the NTP in the participants in their 60s, 70s, 80s, and ≥90s, respectively (p<0.05). Conclusion: Tongue pressure weakness was observed in 40.5% of the healthy community-dwelling older adults. Furthermore, ATP graphs were observed in the patients with tongue pressure weakness. Thus, activities improving the oral function in community-dwelling older adults and systematic oral rehabilitation programs should be devised to promote normal swallowing.
Objective: Transition period is considered from 3 weeks prepartum to 3 weeks postpartum, characterized with dramatic events (endocrine, metabolic, and physiological) leading to occurrence of production diseases (negative energy balance/ketosis, milk fever etc). The objectives of our study were to analyze the periodic concentration of serum beta-hydroxy butyric acid (BHBA), glucose and oxidative markers along with identification, and validation of the putative markers of negative energy balance in buffaloes using in-silico and quantitative real time-polymerase chain reaction (qRT-PCR) assay. Methods: Out of 20 potential markers of ketosis identified by in-silico analysis, two were selected and analyzed by qRT-PCR technique (upregulated; acetyl serotonin o-methyl transferase like and down regulated; guanylate cyclase activator 1B). Additional two sets of genes (carnitine palmotyl transferase A; upregulated and Insulin growth factor; downregulated) that have a role of hepatic fatty acid oxidation to maintain energy demands via gluconeogenesis were also validated. Extracted cDNA (complementary deoxyribonucleic acid) from the blood of the buffaloes were used for validation of selected genes via qRTPCR. Concentrations of BHBA, glucose and oxidative stress markers were identified with their respective optimized protocols. Results: The analysis of qRT-PCR gave similar trends as shown by in-silico analysis throughout the transition period. Significant changes (p<0.05) in the levels of BHBA, glucose and oxidative stress markers throughout this period were observed. This study provides validation from in-silico and qRT-PCR assays for potential markers to be used for earliest diagnosis of negative energy balance in buffaloes. Conclusion: Apart from conventional diagnostic methods, this study improves the understanding of putative biomarkers at the molecular level which helps to unfold their role in normal immune function, fat synthesis/metabolism and oxidative stress pathways. Therefore, provides an opportunity to discover more accurate and sensitive diagnostic aids.
This study aims to develop a new model to obtain the minimum area in circular isolated footings with eccentric column taking into account that the surface in contact with the ground works partially in compression, i.e., a part of the contact area of the footing is subject to compression and the other there is no pressure (pressure zero). The new model is formulated from a mathematical approach based on a minimum area, and it is developed by integration to obtain the axial load "P", moment around the X axis "Mx" and moment around the Y axis "My" in function of σmax (available allowable soil pressure) R (radius of the circular footing), α (angle of inclination where the resultant moment appears), y0 (distance from the center of the footing to the neutral axis measured on the axis where the resultant moment appears). The normal practice in structural engineering is to use the trial and error procedure to obtain the radius and area of the circular footing, and other engineers determine the radius and area of circular footing under biaxial bending supported on elastic soils, but considering a concentric column and the contact area with the ground works completely in compression. Three numerical problems are given to determine the lowest area for circular footings under biaxial bending. Example 1: Column concentric. Example 2: Column eccentric in the direction of the X axis to 1.50 m. Example 3: Column eccentric in the direction of the X axis to 1.50 m and in the direction of the Y axis to 1.50 m. The new model shows a great saving compared to the current model of 44.27% in Example 1, 50.90% in Example 2, 65.04% in Example 3. In this way, the new minimum area model for circular footings will be of great help to engineers when the column is located on the center or edge of the footing.
Backgrounds/Aims: The hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is classified as the advanced stage (BCLC stage C) with extremely poor prognosis, and in current guidelines is recommended for systemic therapy. This study aimed to evaluate the surgical outcomes and long-term prognosis after hepatic resection (HR) for patients who have HCC combined with PVTT. Methods: We retrospectively analyzed 332 patients who underwent HR for HCC with PVTT at ten tertiary referral hospitals in South Korea. Results: The median overall and recurrence-free survival after HR were 32.4 and 8.6 months, while the 1-, 3-, and 5-year overall survival rates were 75%, 48%, and 39%, respectively. In multivariate analysis, tumor number, tumor size, AFP, PIVKA-II, neutrophil-to-lymphocyte ratio, and albumin-bilirubin (ALBI) grade were significant prognostic factors. The risk scoring was developed using these seven factors-tumor, inflammation and hepatic function (TIF), to predict patient prognosis. The prognosis of the patients was well stratified according to the scores (log-rank test, p < 0.001). Conclusions: HR for patients who have HCC combined with PVTT provided favorable survival outcomes. The risk scoring was useful in predicting prognosis, and determining the appropriate treatment strategy for those patients who have HCC with PVTT.
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70
The wall shear stress in the vicinity of end-to end anastomoses under steady flow conditions was measured using a flush-mounted hot-film anemometer(FMHFA) probe. The experimental measurements were in good agreement with numerical results except in flow with low Reynolds numbers. The wall shear stress increased proximal to the anastomosis in flow from the Penrose tubing (simulating an artery) to the PTFE: graft. In flow from the PTFE graft to the Penrose tubing, low wall shear stress was observed distal to the anastomosis. Abnormal distributions of wall shear stress in the vicinity of the anastomosis, resulting from the compliance mismatch between the graft and the host artery, might be an important factor of ANFH formation and the graft failure. The present study suggests a correlation between regions of the low wall shear stress and the development of anastomotic neointimal fibrous hyperplasia(ANPH) in end-to-end anastomoses. 30523 T00401030523 ^x Air pressure decay(APD) rate and ultrafiltration rate(UFR) tests were performed on new and saline rinsed dialyzers as well as those roused in patients several times. C-DAK 4000 (Cordis Dow) and CF IS-11 (Baxter Travenol) reused dialyzers obtained from the dialysis clinic were used in the present study. The new dialyzers exhibited a relatively flat APD, whereas saline rinsed and reused dialyzers showed considerable amount of decay. C-DAH dialyzers had a larger APD(11.70
본 연구에서는 다양한 효능과 기능성 및 향균작용이 있는 �牡牡� 생면에 첨가하여 최적의 조리적용을 연구하고자 하였다. 생면에서 수분함량의 결과는 생 깻잎 즙 0%를 첨가한 대조군이 가장 낮게 나타났으며 이와 반대로 동결 건조한 분말 7% 첨가한 생면이 가장 높은 수분함량을 나타내었다. 생 들깻잎을 첨가한 생면은 시료의 첨가량이 많아질수록 pH가 증가 하였다. 생 들깻잎을 첨가한 생면과 동결 건조한 들깻잎을 첨가한 생면은 L값은 생 들깻잎의 첨가량이 증가 할수록 그 값이 감소하는 경향을 보였다. a값은 생 들깻잎의 첨가량이 증가할수록 유의적으로 감소하는 경향을 보였다. 생 들깻잎을 첨가한 생면의 중량은 생 들깻잎을 첨가할수록 무게가 유의적으로 감소하는 경향을 보였다. 부피의 경우는 중량과 정반대의 결과를 나타냈다. 탁도의 경우는 생 깻잎과 동결 건조한 깻잎의 첨가량이 증가할수록 탁도가 감소하는 경향을 보였다. 생 깻잎을 첨가한 생면의 경도(Hardness)는 생 깻잎의 첨가량이 증가할수록 경도는 유의적으로 감소하는 경향을 보였다. 탄력성(Springiness)과 씹힙성(Chewiness), 응집성(Cohesiveness)은 생 깻잎의 첨가량이 증가할수록 값이 유의적으로 감소하는 경향을 보였다. 깻잎 생즙, 동결 건조 �牡� 분말을 첨가하여 제조한 생면을 미생물 변화는 저장 0일에는 모든 첨가군에서 미생물이 검출되지 않았다. 깻잎의 첨가량이 증가할수록 미생물 균의 수가 줄어들었다. 생 들깻잎을 첨가한 생면의 관능검사를 결과는 외관(Appearance)과 향(Flavor), 색(Color), 맛(Taste), 조직감(Texture)은 9% 첨가가 모든 부분에서 가장 높은 점수를 얻었다. 전체적인기호도(Overall acceptability)는 9% 첨가가 7.67로 가장 높았고, 동결 건조한 들깻잎을 첨가하여 제조한 조리면의 외관, 냄새, 색, 맛, 조직감, 전반적인 품질을 평가항목으로 관능검사를 결과는 외관(Appearance)과 향(Flavor)은 3% 첨가가 7.60으로 가장 높았다. 색(Color)과 맛(Taste)은 3% 첨가가 7.67로 가장 높았다. 조직감(Texture)은 3%와 5% 첨가가 6.87, 6.20로 가장 높았다. 전체적인 기호도(Overall acceptability)는 3%첨가가 7.07로 가장 높았다. 생들깻잎은 9% 첨가시, 동결건조 깻잎은 3% 첨가시 최적의 맛을 나타냈다.
목 적 : 항암치료 중 anthracycline을 사용한 환아들에 대한 후향적 조사를 통해 anthracycline의 축적량과 anthracycline 심독성과의 관계를 알고자 했고 심독성 환아들에 대한 추적 조사를 통해 anthracycline 심독성 환아의 예후를 알고자 하였다. 방 법 : 1995년 1월부터 2000년 12월까지 서울대학교병원 소아과에서 anthracycline을 포함한 항암치료를 시작한 환아를 대상으로 과거 anthracycline 축적량과 심장 초음파 검사 소견, 심독성 발생 유무 등을 조사하였다. 심독성은 좌심실 수축분율이 26% 이하로 감소한 경우로 정하였고 이들을 다시 좌심실 수축분율이 20%가 넘는 경증 심독성과 20% 미만인 중증 심독성으로 분류하였다. Anthracycline 심독성이 발생한 환아들에게 운동 능력과 심장 초음파, 심전도 검사, 흉부 방사선 촬영 등의 추적 검사를 시행하였다. 결 과 : 총 조사대상 환아는 154명이었다. 이 중에서 40명(26.0%)의 anthracycline 심독성이 발생하였으며 경증 심독성이 27명(17.5%), 중증 심독성이 13명(8.4%)이었다. 심독성의 발생률은 anthracycline의 축적량이 증가함에 따라 서서히 증가하다가 축적량이
This study was intended to find out the factors affecting to the IADL, allowing objective assessment of physical function status of increasing elderly populations. The subjects of 635 elderly persons aged over 65 years old who live in Taejon metropolitan city were interviewed during the two-month period from June to July of 2000. The IADL of Older American Resources and Services(OARS), developed in Duke medical college of USA, was interpreted for use. The study results were statistically processed using SPSSWIN(ver 10.0) and conferred the following results: 1. Among the seven items of IADL, the women showed higher rates of 'yes' in items about using the telephone, getting to the places out of walking distance, going shopping for groceries, taking their own medicine while outnumbered by the men only in the item about managing their own money, without significant differences between them in items about preparing their own meals and doing their own housework. 2. In terms of IADL scores,