• Acute and Critical Care
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• 제33권4호
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• pp.252-259
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• 2018

Background: The aim of this study was to investigate the effects of using a systematic approach to tracheostomy care by a clinical nurse specialist and surgical intensivists for patients with a tracheostomy who were transferred from the surgical intensive care unit (SICU) to the general ward. Methods: In this retrospective study, subjects were limited to SICU patients with a tracheostomy who were transferred to the general ward. The study period was divided into a preintervention period (January 1, 2007 to December 31, 2010) and a postintervention period (January 1, 2011 to December 31, 2014), and electronic medical records were used to analyze and compare patient characteristics, clinical outcomes, and readmission to the SICU. Results: The analysis included 44 patients in the preintervention group and 96 patients in the postintervention group. Decannulation time ($26.7{\pm}25.1$ vs. $12.1{\pm}16.0days$, P=0.003), length of stay in the general ward ($70.6{\pm}89.1$ vs. $40.5{\pm}42.2days$, P=0.008), length of total hospital stay ($107.5{\pm}95.6$ vs. $74.7{\pm}51.2days$, P=0.009), and readmission rate of SICU decreased due to T-cannula occlusion (58.8% vs. 5.9%, P=0.010). Conclusions: Using a systematic approach to tracheostomy care in the general ward led to reduction in decannulation time through professional management, which resulted in a shorter hospital stay. It also lowered SICU readmission by solving problems related to direct T-cannula.

• Korean Journal of Radiology
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• 제21권5호
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• pp.572-581
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• 2020

Objective: To evaluate the safety, feasibility, and efficacy of microwave ablation (MWA) for the treatment of primary hyperparathyroidism (PHPT). Materials and Methods: This study enrolled 67 PHPT patients (22 men, 45 women; mean age, 56.0 ± 16.3 years; range, 18-83 years) from January 2015 to December 2018. The laboratory data, including the serum intact parathyroid hormone (iPTH), calcium, phosphorus, and alkaline phosphatase (ALP) levels, were evaluated before MWA and again 2 hours, 1 day, 7 days, 1 month, 3 months, 6 months, 12 months, 18 months, and 24 months after. Results: Complete ablation was achieved with all 72 hyperplastic parathyroid glands found on the 67 patients enrolled, 64 of whom were treated in one session and 3 were treated over two sessions. The technical success rate was 100%. The median follow-up time was 13.6 months (range, 10.0-31.1 months). The clinical success rate was 89.4%. The volume reduction rate was 79.4% at 6 months. Compared to pre-MWA, the serum iPTH, calcium, phosphorus, and ALP levels had significantly improved 6 months post-MWA (iPTH, 157.3 pg/mL vs. 39.2 pg/mL; calcium, 2.75 ± 0.25 mmol/L vs. 2.34 ± 0.15 mmol/L; phosphorus, 0.86 ± 0.20 mmol/L vs. 1.12 ± 0.22 mmol/L; ALP, 79 U/L vs. 54 U/L, respectively; all, p < 0.01). Hoarseness was a major complication in 4 patients (6.0%), but it improved spontaneously within 2-3 months. Conclusion: MWA is safe, feasible, and effective for the treatment of PHPT.

• Asian-Australasian Journal of Animal Sciences
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• 제30권1호
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• pp.125-132
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• 2017

Objective: Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Methods: Through investigation of 41 dairy farms, weight reduction and volatile solids (VS), total nitrogen (TN), and total phosphorus (TP) changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i) experiment, ii) reference, and iii) theoretical changes in phosphorus content (${\Delta}P=0$). Results: The data revealed the nutrient loading coefficients (NLCs) of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. Conclusion: As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management.

• 유기물자원화
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• 제11권4호
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• pp.79-89
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• 2003

본 연구는 생활폐기물을 호기성분해 개념에서 유기물을 분해 안정화시킬 때 적정한 환경인자들을 도출, 검토하기 위해서 가정에서 배출되는 일반생활폐기물을 각각의 비율에 따라 섞은 후 함수율을 55%, 60%로 조절하여 분해 안정화정도를 평가하였다. VS량의 변화는 6번 반응기를 제외하고는 모든 반응기에서 초기에 투입된 음식물량이 모두 분해가 된 것으로 판단되었고, 1, 2, 3, 4번 반응기는 비슷한 분해정도를 보여 비닐/플라스틱의 첨가가 통기개량제로서의 역할을 한 것으로 사료되었다. 반응기별 온도는 모든 반응기의 최고 온도가 약 $57{\sim}59^{\circ}C$정도로 측정되었고, VS량의 변화와 비슷하게 1, 2, 3, 4번 반응기가 최고온도에서 지속기간이 5, 6번 반응기보다는 약 2~4일정도 더 지속되어 분해반응이 더 잘 일어난 것으로 판단되었으며, $CO_2$ 발생량도 온도 변화와 비슷한 경향을 나타내고 있다. 함수율 변화는 미생물의 산화열로 증발된 수분의 원활한 배출이 이루어지지 않은 관계로 수분 감소율은 모든 반응기에서 낮게 측정되었다. pH는 음식물쓰레기로 인하여 초기에는 약산성이었으나, 반응이 진행됨에 따라 pH가 상승하여 일반적인 경향과 비슷하게 측정되었다. 전기전도도와 C/N비는 전체적으로 소폭증가하는 경향을 보였다. 침하량과 무게감소율도 위의 다른 인자들과 비슷한 경향을 보였다. 즉, 1, 3번 반응기와 2, 4번 반응기가 더 큰 침하율과 무게감소율을 보였다.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1329-1334
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• 2006

The electrochemical reduction of coumarin, 7-acetoxy-4-methyl coumarin (AMC), and 7-acetoxy-4-bromomethyl coumarin (ABMC), in 0.1 M tetraethyl ammonium perchlorate/acetonitrile solution was carried out by direct current, differential pulse polarography, cyclic voltammetry, and controlled potential coulometry. The electrochemical reduction of ABMC was proceeded through three steps of electron transfer coupled with the chemical reactions. The color of solution was changed to yellow when the carbonyl group was reduced during 2nd step (-1.8 volts) and independented with cleavage of bromo group. Highest fluorescence intensity showed when the electrochemical reduction of AMC was controlled at near the potential (-2.3 volts vs. Ag/AgCl).

• Environmental Engineering Research
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• 제10권4호
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• pp.165-173
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• 2005

Nano-sized iron particles were synthesized by reduction of $Fe^{3+}$ in aqueous solution under two reaction conditions, aerobic and anaerobic, and the reactivity of iron was tested by reaction with trichloroethene (TCE) using a batch system. Results showed that iron produced under anoxic condition for both synthesis and drying steps gave rise to iron with higher reduction reactivity, indicating the presence of oxygen is not favorable for production of nano-sized iron deemed to accomplish reactivity enhancement from particle sized reduction. Nano-sized iron sample obtained from the anoxic synthesis condition was further characterized using various instrumental measurements to identity particle morphology, composition, surface area, and particle size distribution. The scanning electron microscopic (SEM) image showed that synthesized particles were uniform, spherical particles (< 100 nm), and aggregated into various chain structures. The effects of other synthesis conditions such as solution pH, initial $Fe^{3+}$ concentration, and reductant injection rate on the reactivity of nano-sized iron, along with standardization of the synthesis protocol, are presented in the companion paper.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.11-17
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• 2020

Copper has been proved to be the best catalyst for electrochemical CO2 reduction reaction, however, for optimal efficiency and selectivity, its performance requires improvements. Electrochemical CO2 reduction reaction (RR) using CuO nanowire electrode was performed with different concentrations of KHCO3 electrolyte (0.1 M, 0.5 M, and 1 M). Cu(OH)2 was formed on Cu foil, followed by thermal-treatment at 200℃ under the air atmosphere for 2 hrs to transform it to the crystalline phase of CuO. We evaluated the effects of different KHCO3 electrolyte concentrations on electrochemical CO2 reduction reaction (RR) using the CuO nanowire electrode. At a constant current (5mA), low concentrated bicarbonate exhibited a more negative potential -0.77 V vs. Reversible Hydrogen Electrode (RHE) (briefly abbreviated as VRHE), while the negative potential reduced to -0.33 VRHE in the high concentration of bicarbonate solution. Production of H2 and CH4 increased with an increased concentration of electrolyte (KHCO3). CH4 production efficiency was high at low negative potential whereas HCOOH was not influenced by bicarbonate concentration. Our study provides insights into efficient, economically viable, and sustainable methods of mitigating the harmful environmental effects of CO2 emission.

• 대한환경공학회지
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• 제28권1호
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• pp.61-66
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• 2006

슬러리 형태의 돈사폐수로부터 자원회수와 질소제거를 위하여 순차적으로 ADEPT(Anaerobic digestion elutriated phased treatment) 공정과 SHARON(Single reactor system High Ammonium Removal Over nitrite)-ANAMMOX(Anaerobic ammonium oxidation)공정을 결합하여 운전하였다. ADEPT 공정은 부하율 3.95 gSCOD/L-day에서 운전되었고, SCOD 생성율과 산생성율은 각각 5.3 gSCOD/L-day와 3.3 gVFAs/L-day(as COD)였다. 가수분해에 의한 VS감소와 SCOD생성율은 각각 13%와 0.19 $gSCOD_{prod}/gVS_{feeding}$였으며, 산생성율은 0.80 $gVFAs/gSCOD_{prod.}$였다. 메탄발효조에서 가스생성율과 메탄함량은 각각 2.8 L/day($0.3m^3CH_4/kgCOD_{removal}\;@STP$) 및 77%였다. 운전조건에서 $NH_4-N$ 94.1% (TKN으로서 86.5%) 및 T-P 87.3%가 제거되었다.

• 한국수산과학회지
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• 제45권5호
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• pp.472-479
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• 2012

The formation of volatile fatty acids(VFAs) and changes in pH, oxidation and reduction potential(Eh) and acid volatile sulfide(AVS) with the addition of yellow clay were investigated using microcosm systems to examine the effects of yellow clay dispersion on the anaerobic decomposition of Cochlodinium polykrikoides in marine sediments. The acetate concentration reached a maximum by day 4 and was 1.2-1.8 fold less in the sample treated with yellow clay compared to the untreated sample (224-270 vs. 333 uM). The formate concentration reached a maximum by day 1 and was 1.3-2.8 fold less in the sample treated with yellow clay compared to the untreated sample (202-439 vs. 563 uM). The propionate concentration reached a maximum by day 2 and was 1.5-1.8 fold less in the sample treated with yellow clay compared to the untreated sample (32.6 vs. 57.2 uM). After the amounts of acetate, formate and propionate peaked the levels dropped dramatically due to the utilization by sulfate reducing bacteria. The Eh of the samples treated with yellow clay was similar to the untreated sample on day 0 but was higher in the sample treated with yellow clay(140-206 mV) from days 4 to 17. AVS started to form on day 3 and this was sustained until day 6, and 1.2-2.2 fold less was produced in the sample treated with yellow clay compared to the untreated sample (40.2-69.3 vs. 83.2-93.8 mg/L). Accordingly, during the anaerobic decomposition of C. polykrikoides in marine sediments, yellow clay dispersal seems to suppress the reduction state of Eh and the formation of volatile fatty acids(acetate, formate and propionate) used as an energy source by sulfate reducing bacteria, indicating that this process controls the production of hydrogen sulfide that negatively affects marine organisms and the marine sediment environment.

• 한국세라믹학회지
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• 제20권4호
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• pp.356-360
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• 1983

The photocurrent vs. potential characteristics of the $TiO_2$ ceramic electrodes have been investigated as functions of numerous variables including sample purity hydrogen reduction condition and pH of the electrolyte. The difference inphotoresponse between 99.99% and 98.5% $TiO_2$ electrodes was due to electron trapping effect. As the hydrogen reducing temperature of $TiO_2$ electrodes were increased the photocurrent was also increased to certain condition and then decreased. These results can be explained by the behavior of oxygen vacancies.