• Membrane and Water Treatment
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• v.8 no.4
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• pp.337-353
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• 2017

Membrane fouling at different solids retention times (SRT) (7, 12 and 20 days) was studied under well-controlled conditions in a laboratory-scale aerobic submerged membrane bioreactor under constant biomass concentration using a synthetic high strength wastewater. An increase in SRT was found to improve membrane performance and this correlated to changes in the total production of bound extracellular polymeric substances (EPS), and the composition and properties of bound EPS using X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared spectroscopy (FTIR) and floc sizes. A larger amount of total bound EPS was found at the lowest SRT (7 days) tested but the ratio of proteins (PN) to carbohydrates (CH) in bound EPS increased with an increase in SRT. Similarly, the quantity of soluble microbial products (SMP) decreased with an increase in SRT and the SMP PN/CH ratio increased with an increase in SRT. SMP concentrations positively correlated to the percentage of membrane pore blocking resistance. The quantity of total bound EPS and total SMP positively corresponded to the membrane fouling rate, while the PN/CH ratio in the bound EPS and SMP negatively correlated to the membrane fouling rate. The results show that both the quantity and composition of bound EPS and SMP and floc sizes are important in controlling membrane fouling.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.382-388
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• 2008

This study was initiated to elucidate the relation between the toxicity of $Cr^{6+}$, $Zn^{2+}$, and $Cd^{2+}$ and sludge age (Solids retention time, SRT). The effect of SRT on the toxicity of $Cr^{6+}$, $Zn^{2+}$, and $Cd^{2+}$ in activated sludge system was investigated with INT-dehydrogenase assay. Experimental results showed that the inhibitory effects of $Cr^{6+}$, $Zn^{2+}$, and $Cd^{2+}$ were reduced as the sludge age increased from SRT 5 d to SRT 25 d. It is noteworthy that the experimental results enabled to determine the relative toxicity of the tested metals depending on the sludge age. At the SRT of 5 and 9 days, the order of toxicity of the three metals to the activated sludge was $Cr^{6+}$ > $Zn^{2+}$ > $Cd^{2+}$ (the $IC_{50}$ value of $Cr^{6+}$, $Zn^{2+}$, and $Cd^{2+}$ was 16.15, 25.90, and 32.49 mg/L, respectively) and $Zn^{2+}$ > $Cr^{6+}$ > $Cd^{2+}$ (the $IC_{50}$ value of $Cr^{6+}$, $Zn^{2+}$, and $Cd^{2+}$ was 39.12, 27.93, and 42.31 mg/L, respectively), respectively. However, the toxicity of three metals was almost same at the SRT of 14 and 25 days (the range of $IC_{50}$ in SRT 14 and 25 days was from 49.80 mg/ L to 53.44 mg/L among three heavy metals). This results would be explained by that the quantity of biopolymer formed in short SRT was small, whereas that in long SRT was large. Consequently, it is recommended that sludge age be maintained at long SRT in order to avoid the toxicity inhibition of heavy metals such as $Cr^{6+}$, $Zn^{2+}$, and $Cd^{2+}$.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.421-431
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• 2006

Statement of problem : Accurate impression is essential to success of implant prostheses. But there have been few studies about the accuracy of fixture-level impression technique in internal connection implant system. Purpose: This study evaluated the accuracy of splinted fixture-level impression technique using clinical methods and the effect of internal hex on fit of superstructure in internal connection implant system (Astra Tech). Material and method : Two metal master frameworks made from two abutments (Cast-to Abutment ST) each for parallel and divergent conditions and a corresponding. passively fitting, dental stone master cast with four future replicas (Fixture Replica ST) were fabricated. Ten dental stone casts were made with vinyl polysiloxane impressions from the master cast by acrylic resin splinted fixture-level impression technique. To evaluate the accuracy of impression technique, the fit of master frameworks for test models was evaluated using screw resistance test (SRT) and one-screw test. The results of SRT were recorded as SRT values from grade 1 to grade 5 by 1/4 turn. And to evaluate the effect of hex on fit of superstructure, the same tests were performed after removing hexes of master frameworks. Results: 1. There was only one case (2.5%) showing SRT value of test model below ade 2 in total before and after removing hexes of master frameworks. And, by removing hexes. SRT values decreased in only one test model (5%) and did not change in 17 test models (85%). 2. SRT values of the 1$^{st}$ screws were grade 2 in 80% of cases before, and grade 1 in 80% of cases after removing hexes. And, by removing hexes, SRT values decreased in 72.5% of cases. 3. SRT values of the 2$^{nd}$ screws were grade 3 in 85% of cases before, and grade 3 in 95% of cases after removing hexes. And, by removing hexes, SRT values did not change in 85% of cases. 4. There were only 2 cases regarded as acceptable fit by one-screw test, and SRT values of 2$^{nd}$ screws of both cases were grade 2. Conclusion. Within the limitations of this study, future-level impression of internal connection implant system is considered to obtain inaccurate working cast, even using acrylic resin splinted impression technique. And, it is considered to be unable improve the fit to remove the hexes of implant restoration.

• Journal of Genetic Medicine
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• v.17 no.2
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• pp.62-67
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• 2020

Purpose: Eliglustat is an oral substrate reduction therapy (SRT) approved for adults with Gaucher disease type I (GD1) who are extensive, intermediate, or poor CYP2D6 metabolizers. Here we report one-year experience of eliglustat switch therapy from long-term enzyme replacement therapy (ERT) in three adult patients with GD1. Materials and Methods: Medical history, clinical (hemoglobin concentration, platelet count, and bone mineral density) and biochemical parameters (angiotensin converting enzyme, total acid phosphatase, and lyso-gb1) of the patients were collected and evaluated by retrospective review of medical records at every 3, 6, or 12 month after switch to SRT. Results: Patient 1 was a 43-year old female diagnosed GD1 and her clinical and biochemical parameters were stabilized for more than 20 years by ERT. Due to the burden of regular hospital visit, she switched to SRT. During one-year of SRT, clinical parameters and biomarkers were maintained stable. However, after suffering acute febrile illness during SRT, she decided to re-switch to ERT due to concerns about drug interaction. Patient 2 was 41-year old male, younger brother of patient 1 and Patient 3 was 31-year old male. They switched to SRT in clinically stable condition with long-term ERT. The one-year SRT was tolerable without specific safety issue and the clinical parameters were maintained stable. Conclusion: One-year eliglustat therapy in three adult patients with GDI was generally tolerable and effective for maintaining the clinical parameters and biomarkers. However, the drug compliance, concurrent drug interactions, and long-term safety of eliglustat should be carefully monitored.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.517-524
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• 2001

This paper describes a design of radix-2 SRT divider unit, which supports IEEE-754 floating-point standard, using redundant binary number system (RBNS). With the RBNS, the partial quotient decision logic can operate about 20-% faster, as well as can be implemented with a simple hardware when compared to the conventional methods based on two's complement arithmetic. By using a new redundant binary adder proposed in this paper, the mantissa divider is efficiently implemented, thus resulting in about 20% smaller area than other works. The divider unit supports double precision format, five exceptions and four rounding modes. It was verified with Verilog HDL and Verilog-XL.

• Journal of environmental and Sanitary engineering
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• v.4 no.1 s.6
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• pp.43-52
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• 1989

A synthetic wastewater composed of powdered baby food and inorganic nutrients was treated by five 3.6L anaerobic reactors in order to test the relationship between solids retention time (SRT) and media surface ratio, and the removal efficiencies of organic substrate. Of the five reactors, four were semi-continuously fed stirred-tank reactors and one continuously-stirred batch reactor. The influent was 7430mg/L in COD, 7120 mg/L $BOD_L$ and 6350mg/L in $BOD_5$, respectively. Operating temperature was $35{\pm}1^{\circ}C$ and pH in the range 6.9 to 7.2. In this experimental study it was found that a linear relationship existed, within the experiment range, between SRT and media surface ratio, and that SRT and removal efficiency increased with increasing media surface ratio. The substrate removal efficiencies were 82.7 to $88.2\%$ in COD, 82.9 to $88.4\%$ in $BOD_L$ and 83.3 to $88.7\%$ in $BOD_5$, respectively.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.140-147
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• 2010

In existing design method for aeration tank water temperature was considered as governing variable for applying safety factor. This study tried a few new approach of aeration tank design using SOUR at various temperature conditions. Specific substrate utilization rate (U) and specific oxygen uptake rate (SOUR) both were analyzed at various temperature and SRT. The laboratory scale reactor was operated on various temperature ($10^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$) and SRT (5day, 10day, 20day, 30day). In this study, SOUR tended to increase with the temperature increased. On the other hand, SOUR tended to decrease when SRT increased from 5 days to 30 days. Empirical equations were obtained SOUR=a/SRT+b and $SOUR=(a/m){\cdot}U+(b-a(n/m))$ from the relationship between SRT, U and SOUR. Empirical equations shows the possibility as a new design method for the aeration basin.

• Membrane and Water Treatment
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• v.10 no.2
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• pp.179-189
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• 2019

This study aimed to investigate the effect of temperature and solid retention time (SRT) on membrane fouling in a membrane bioreactors (MBRs). For this purpose, a lab-scale submerged MBR system was used. This system operated at two SRTs of 15 and 5 days, three various temperatures (20, 25 and $30^{\circ}C$) and hydraulic retention time (HRT) of 8 h. The results indicated that decreased the cake layer resistance and increased particles size of foulant due to increasing temperature and SRT. Fourier transform infrared (FTIR) analysis show that the cake layer formed on the membrane surface, contained high levels of proteins and especially polysaccharides in extracellular polymeric substances (EPS) but absorbance intensity of EPS functional groups decreased with temperature and SRT. EEM analysis showed that the peak on the range of Ex/Em=220-240/350-400 in SRT of 15 and temperature of $30^{\circ}C$ indicates the presence of fulvic acid in the cake. In addition, as the temperature rise from 20 to $30^{\circ}C$, concentration of soluble microbial products (SMP) increased and COD removal reached 89%. Furthermore, the rate of membrane fouling was found to increase with decreasing temperature and SRT.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.139-146
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• 2023

Three dogs were referred with epistaxis and facial deformity. Computed tomography (CT) scan identified masses in the bilateral nasal cavity with soft tissue attenuation and contrast enhancement. These masses had caused adjacent bones lysis, especially lysis of cribriform plate that extended to the intracranial region. Base on histopathology and CT imaging results, tumors were diagnosed as nasal carcinomas at stage 4. Three dogs were treated with stereotactic radiation therapy (SRT). These dogs received 30-35 Gy from 3-5 daily treatments (7-10 Gy per treatment). The sizes of tumors decreased the most on follow-up CT images at one month after treatment. Recurrence was confirmed between 3 and 5 months after completing SRT. The survival time of dogs treated with SRT were 110, 190, and 210 days, respectively. This study confirmed that SRT could treat canine nasal carcinomas with cribriform plate lysis without causing serious radiation toxicities. Follow-up CT examination is considered at 1 month and 3 to 6 months after SRT to accurately evaluate the prognosis and the timing of recurrence.

• Research in Mathematical Education
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• v.3 no.1
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• pp.23-34
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• 1999

This paper presents a summary of the Scientific Research Training (SRT) in Liaocheng Teachers University, which is a representative of normal universities and teachers' colleges in China. There is a survey on the situation of SRT in China systematically and historically. Tentative ideas about SRT in future are targeted at the teachers and heads of departments in China.