• 한국연초학회지
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• 제28권1호
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• pp.51-57
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• 2006

This study was carried out to improve and evaluate the analytical method for determination of potassium in tobacco leaf by various pre-treatment techniques. The time requirment of various pre-treatments was about 10 hour for dry ashing and 6 hour for microwave digestion and 3 hour for sonication. The results of recover in both pre-treatment techniques, microwave digestion and sonication, is greater than 85 % stably with reproducibility(RSD %) on replicates of less than 3 %. However the mean values for microwave digestion were lower than certified standard value of NlST SRM. Compared to the other pre-treatment techniques, analytical results for sonication technique strictly improved the accuracy and precision. In conclusion, the use of the simple sonication technique seems to be efficient for the determination of potassium in tobacco leaf in consideration for both the accuracy and reproducibility.

• International journal of advanced smart convergence
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• 제5권2호
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• pp.18-23
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• 2016

Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This paper preproposal stage investigated the effect of different pre-treatments on microalgae cell wall, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. This Paper present optimum approach to degradation of the cell wall by ultra-sonication with practical design specification parameter for ultrasound based pretreatment system. As a result of this paper presents, a microalgae system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. As a conclusion on this result, Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system.

• 한국식품조리과학회지
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• 제32권6호
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• pp.716-723
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• 2016

Purpose: This study was conducted to improve the quality characteristics of pork intestine through different pretreatment processes. Methods: We washed pork intestine by both physical (tap water, UV, and sonication) and chemical methods (alcohol, acetic acid, flour and NaCl) as pretreatment process. The physicochemical (pH, color, volatile basic nitrogen (VBN), and 2-thiobarbituric acid reactive substances (TBARS)) and microbial properties of pre-treated pork small intestine were evaluated. Results: The nature of the pretreatment method influenced the pH value of pork small intestine. The acetic acid treatment resulted in the lowest pH value. In physical method, the color value and the number of microorganism were significantly affected by sonication as compared to other treatments. TBARS value of pork small intestine after all the treatments was lower than the control. However, VBN exhibited no significant differences in its value irrespective of the nature of treatment. Appearance and control exhibited lowest value in response to sonication treatment. However, off-flavor and overall acceptability were higher in sonication treatment than other treatments. In chemical method involving NaCl and flour treatments, lightness and redness were lower than other treatments. Lowest VBN and TBARS values were noted in alcohol and acetic acid treatmentsand no growth of E. coli and coliform bacteria was observed. The other treatments resulted in lower values of VBN, TBARS, and microbial counts than the control. Appearance and color value after alcohol, acetic acid, and flour treatment were lower than the control and NaCl treatment. Off-flavor and overall acceptability of by-product after alcohol, flour, and NaCl treatments were higher than the control and acetic acid treatment. Conclusion: Overall, we present NaCl treatment and sonication treatment in the form of a combination pretreatment method as the optimal condition for processing pork intestine.

• 상하수도학회지
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• 제38권2호
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• pp.109-117
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• 2024

In this study, various pre-treatment methods were evaluated for microalgae separation. These methods aimed to facilitate safe, rapid, and cost-effective online imaging for real-time observation and cell counting. As pre-treatment techniques, heating, chemical hydrolysis, heating combined with chemical hydrolysis, and sonication were employed. The effectiveness of these methods was evaluated in the context of online imaging quality through experimentation on cultivated microalgae (Chlorella vulgaris and Scenedesmus quadricauda). The chemical treatment method was found to be inappropriate for improving image acquisition. The heating pre-treatment method exhibited a drawback of prolonged cell dispersion time. Additionally, the heating combined with chemical hydrolysis method was confirmed to have the lowest dispersion effect for Chlorella vulgaris. Conversely, ultrasonication emerged as a promising technique for microalgae separation in terms of repeatability and reproducibility. This study suggests the potential for selecting optimal pre-treatment methods to effectively operate real-time online monitoring devices, paving the way for future research and applications in microalgae cultivation and imaging.

• 한국물환경학회지
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• 제32권6호
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• pp.600-627
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• 2016

Korea is one of the countries with a large veterinary antibiotics market, although antimicrobial resistance in bacteria is becoming a serious issue in many countries. The Korean government started to take interest in estimating the effects of livestock manure on rivers and agricultural soils and in monitoring of heavy metals, organic pollutants and antibiotics in the ambient water and soil. In this paper, pre-treatment methods to separate the selected antibiotics from solid samples were reviewed. It is essential to select an efficient and appropriate procedure for pre-treatment due to the high proportion of proteins and organics in biosolid samples. Pre-treatment consists of extraction followed by clean-up. Initially, homogenized samples were extracted by sonication, mechanical agitation or pressurized liquid extraction with methanol/acetonitrile/water mixture under acidic/basic conditions depending on the compound. However, aminoglycosides and colistin were extracted with 5% trichloroacetic acid and HCl, respectively. Since the ${\beta}-lactams$ are easily decomposed in acidic and basic conditions, they were extracted in neutral pH. Filtration with a membrane (pore size, $0.2{\mu}m$) or solid phase extraction with HLB and methanol, as eluents, was normally applied for the clean-up. At least, three different pre-treatment procedures should be adopted to screen all the selected antibiotics in solid samples.

• 한국물환경학회지
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• 제25권5호
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• pp.720-726
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• 2009

We investigated the most effective pre-treatment processes and LC/MS/MS condition for microcystins analysis. With a step-by-step pre-treatment, efficiencies of several established methods were compared. At the level of cell burst, sonication method was found to be the most efficient. As a mycrocystins first extraction solvent, 5% acetic acid showed the highest efficiency. An isolation and recovery rate of mycrocystins of ODS Sep-Pak $C_{18}$ cartridge was higher than HLB SPE cartridge. As a final elution solvent from cartridge, 100% MeOH had a better efficiency than others. Using a LC/MS/MS, effective analytical methods were established. C18 reverse column was used and gradient elution was performed with using acetonitrile, 0.1% formic acid as a mobile phase. We analysed to 0.8 mL/min flow rate fit to the $5{\mu}m$ particle size column and $55^{\circ}C$ housing temperature. The validity of established analytical method was evaluated that MDL as average $0.050{\pm}0.014{\mu}g/L$ and LOQ as average $0.160{\pm}0.045{\mu}g/L$ had a good sensitivity over 40 magnification rather than $2{\mu}g/L$ detection limit of HPLC.

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.846-853
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• 2024

Adzuki bean (Vigna angularis), which provides plant-based proteins and functional substances, requires a long soaking time during processing, which limits its usefulness to industries and consumers. To improve this, ultrasonic treatment using high pressure and shear force was judged to be an appropriate pretreatment method. This study aimed to determine the optimal conditions of ultrasound treatment for the improved hydration of adzuki beans using the response surface methodology (RSM). Independent variables chosen to regulate the hydration process of the adzuki beans were the soaking time (2-14 h, X₁), treatment intensity (150-750 W, X₂), and treatment time (1-10 min, X₃). Dependent variables chosen to assess the differences in the beans post-immersion were moisture content, water activity, and hardness. The optimal conditions for treatment deduced through RSM were a soaking time of 12.9 h, treatment intensity of 600 W, and treatment time of 8.65 min. In this optimal condition, the values predicted for the dependent variables were a moisture content of 58.32%, water activity of 0.9979 a_w, and hardness of 14.63 N. Upon experimentation, the results obtained were a moisture content of 58.28 ± 0.56%, water activity of 0.9885 ± 0.0040 a_w, and hardness of 13.01 ± 2.82 g, confirming results similar to the predicted values. Proper ultrasound treatment caused cracks in the hilum, which greatly affects the water absorption of adzuki beans, accelerating the rate of hydration. These results are expected to help determine economically efficient processing conditions for specific purposes, in addition to solving industrial problems associated with the low hydration rate of adzuki beans.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2049-2056
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• 2014

A simple method for exfoliating pristine graphite to yield mono-, bi-, and multi-layers of graphene sheets as a highly concentrated (5.25 mg/mL) and yielded solution in an organic solvent was developed. Pre-thermal treatment of pristine graphite at $900^{\circ}C$ in a sealed stainless steel bath under high pressures, followed by sonication in 1-methyl-2-pyrrolidinone solvent at elevated temperatures, produced a homogeneous, well-dispersed, and non-oxidized graphene solution with a low defect density. The electrical conductivities of the graphene sheets were very high, up to 848 S/cm. These graphene sheets were used to fabricate graphene-polyimide nanocomposites, which displayed a higher electrical conductivity (1.37 S/m) with an improved tensile strength (95 MPa). The synthesized graphene sheets and nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy.

• 한국수소및신에너지학회논문집
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• 제21권6호
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• pp.580-586
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• 2010

Acid and alkali pretreatments were applied to tofu processing waste (TPW) to increase the solubility of ingredients in TPW. Pretreatment at 1.0% of HCl and 2.5% of NaOH condition resulted in the increase of SCOD concentration from 3.2 g COD/L to 27 g COD/L and 33 g COD/L, respectively. The acid and alkali-pretreated TPW was studied for its fermentative $H_2$ production capacity in batch mode using a thermophillic mixed culture. Alkali pretreatment on presence of 2.5% NaOH exhibited more soluble portion released compared to acid pretreatment using HCl, however the $H_2$ production from acid pretreated TPW was better than alkali-pretreated TPW probably due to the sodium inhibition on microbial activity. In addition, sewage sludge was externally added to the acid-pretreated (1.0% HCl) TPW by 20% (on volume basis). Average H2 production rate was increased from 31 to 78 ml/L-broth/hr, and it was attributed to the high buffer capacity and abundant nutrients especially divalent cation in sewage sludge.