• Resources Recycling
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• v.31 no.3
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• pp.61-72
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• 2022

We investigated the electrochemical behavior of Sn (93.0 %)-Ag (4.06 %)-Cu (0.89 %) during electrolysis of Pb-free solder waste to recover tin and silver. A thin strip of the solder waste produced by high-temperature melting and casting was used as a working electrode to perform electrochemical analysis. During anodic polarization, the current peak of an active region decreased with an increase in the concentration of sulfuric acid used as an electrolyte. This resulted in the electro-dissolution of the working electrode in the electrolyte (1.0 molL^-1 sulfuric acid) for a constant current study. The study revealed that the thickening of an anode slime layer at the working surface continuously increased the electrode potential of the working electrode. At 10 mAcm^-2, the dissolution reaction continued for 25 h. By contrast, at 50 mAcm^-2, a sharp increase in the electrode potential stopped the dissolution in 2.5 h. During dissolution, silver enrichment in the anode slime reached 94.3% in the 1 molL^-1 sulfuric acid electrolyte containing a 0.3 molL^-1 chlorine ion, which was 12.7% higher than that without chlorine addition. Moreover, the chlorine enhanced the stability of the dissolved tin ions in the electrolyte as well as the current efficiency of tin electro-deposition at the counter electrode.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.5
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• pp.313-323
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• 2022

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, and it corresponds highly with exercise intensity. Here, we induced AF in mice using acetylcholine (ACh)-CaCl₂ for 7 days and aimed to determine the appropriate exercise intensity (no, low, moderate, high) to protect against AF by running the mice at different intensities for 4 weeks before the AF induction by ACh-CaCl₂. We examined the AF-induced atrial remodeling using electrocardiogram, patch-clamp, and immunohistochemistry. After the AF induction, heart rate, % increase of heart rate, and heart weight/body weight ratio were significantly higher in all the four AF groups than in the normal control; highest in the high-ex AF and lowest in the low-ex (lower than the no-ex AF), which indicates that low-ex treated the AF. Consistent with these changes, G protein-gated inwardly rectifying K⁺ currents, which were induced by ACh, increased in an exercise intensity-dependent manner and were lower in the low-ex AF than the no-ex AF. The peak level of Ca²⁺ current (at 0 mV) increased also in an exercise intensity-dependent manner and the inactivation time constants were shorter in all AF groups except for the low-ex AF group, in which the time constant was similar to that of the control. Finally, action potential duration was shorter in all the four AF groups than in the normal control; shortest in the high-ex AF and longest in the low-ex AF. Taken together, we conclude that low-intensity exercise protects the heart from AF, whereas high-intensity exercise might exacerbate AF.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.75-87
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• 1996

This review is presented under the following headings: 1.Introduction 1.1 Brief review of the properties of AlN 1.2 Historical survey of work on ceramic and single crystal AlN 2.Thermochemical background 3.Crystal growth 4.Doping 5.Potential applications and future work The known properties of AlN which make it of interest for various are discussed briefly. The properties include chemical stability, crystal structure and lattice constants, refractive indices and other optical properties, dielectric constant, surface acoustic wave velocity and thermal conductivity. The history of work in single crystals, thin films and ceramics are outlined and the thermochemistry of AlN reviewed together with some of the relevant properties of aluminium and nitrogen; the problems encountered in growing crystals of AlN are shown to arise directly from these thermochemical relationships. Methods have been reported in the literature for growing AlN crystals from melts, solution and vapour and these methods are compared critically. It is proposed that the only practicable approach to the growth of AlN is by vapour phase methods. All vapour based procedures share the share the same problems: $.$the difficulty of preventing contamination by oxygen & carbon $.$the high bond energy of molecular nitrogen $.$the refractory nature of AlN (melting point~3073K at 100ats.) $.$the high reactivity of Al at high temperatures It is shown that the growth of epitactic layers and polycrystalline layers present additional problems: $.$chemical incompatibility of substrates $.$crystallographic mismatch of substrates $.$thermal mismatch of substrates The result of all these problems is that there is no good substrate material for the growth of AlN layers. Organometallic precursors which contain an Al-N bond have been used recently to deposit AlN layers but organometallic precursors gave the disadvantage of giving significant carbon contamination. Organometallic precursors which contain an Al-N bound have been used recently to deposit AlN layers but organometallic precursors have the disadvantage of giving significant carbon contamination. It is conclude that progress in the application of AlN to optical and electronic devices will be made only if considerable effort is devoted to the growth of larges, pure (and particularly, oxygen-free) crystals. Progress in applications of epi-layers and ceramic AlN would almost certainly be assisted also by the availability of more reliable data on the pure material. The essential features of any stategy for the growth of AlN from the vapour are outlined and discussed.

• Journal of Life Science
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• v.34 no.10
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• pp.691-700
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• 2024

Frutobacillus spp. strains (Fs) were isolated from honeybee larvae to evaluate their functionality and potential use as probiotics. Anti-microbial activity was generally observed in F strains against Gram-negative, Gram-positive, and yeast strains, with F2 and F3 being superior, particularly F2. Kerosene emulsification was similarly observed in strains other, except for F4. Emulsification analysis based on carbon sources showed that F2 had high emulsification in the presence of fructose but lower than the standard strain and 16S rDNA sequence analysis revealed that the F2 was identified as Fructobacillus fructosus. The growth curve of F2 showed maximum growth at 18 hr, followed by a slight increase. Furthermore, antimicrobial activity and pH showed maximum and minimum values at 18 hr, respectively, and remained constant thereafter. Lactic acid content showed a slight decrease after reaching its maximum value at 24 hr of culture. Acid resistance was observed up to pH 2.5, but completely lost at pH 2.0. Bile acid resistance was generally strong. F2's adhesion to mucin was higher compared to S. Typhimurium, which increased until 18 hr of culture and then decreased. Enzyme activity according to anaerobic culture time was high for carboxymethylcellulase (CMCase), avicelase, and mannase, regardless of the presence of fructose. Auto- and co-aggregation were higher compared to the standard strain, and surface hydrophobicity was high for chloroform, which indicates electron donor properties. Therefore, the Fructobacillus fructosus F2 can be considered a potential probiotic due to its excellent anti-microbial, emulsification, acid resistance, bile resistance, CMCase, mannase, and auto- and co-aggregation properties.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.503-511
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• 2008

An edible marine red alga, Grateloupia filicina, collected from Jeju Island of Korea was hydrolyzed by cheap food-grade carbohydrases (Viscozyme, Celuclast, AMC, Termamyl, and Ultraflo) to investigate its anticoagulant activity. Among the tested enzymatic extracts of G. filicina, a Termamyl extract showed the highest anticoagulant activity. Anion-exchange chromatography on DEAE-cellulose and gel-permeation chromatography on Sepharose-4B were used to purify the active polysaccharide from the crude polysaccharide fraction of G. filicina. The purified sulfated polysaccharide (0.42 sulfate/total sugar) showed ${\sim}1,357kDa$ molecular mass and was comprised mainly of galactose(98%) and 1-2% of glucose. The sample showed potential anticoagulant activity on activated partial thromboplastin time (APTT) thrombin time (TT) assays. The purified G. filicina anticoagulant (GFA) inhibited the coagulation factor X (92%), factor II (82%), and factor VII (68%) of the coagulation cascade, and the molecular interaction (protein-polysaccharide) was highly enhanced in the presence of ATIII (antithrombin III). The dissociation constant of polysaccharide towards serine proteins decreased in the order of FXa (58.9 nM) >FIIa (74.6 nM) >FVII (109.3 nM). The low/less cytotoxicity of the polysaccharide benefits its use in the pharmaceutical industry; however, further studies that would help us to elucidate the mechanism of its activity are needed.

• Journal of Microbiology and Biotechnology
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• v.19 no.4
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• pp.339-345
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• 2009

We evaluated the activity and abundance of the crude-oil-degrading bacterium Nocardia sp. H17-1 during bioremediation of oil-contaminated soil, using real-time PCR. The total petroleum hydrocarbon(TPH) degradation rate constants(k) of the soils treated with and without H17-1 were $0.103\;d^{-1}$ and $0.028\;d^{-1}$ respectively. The degradation rate constant was 3.6 times higher in the soil with H17-1 than in the soil without H17-1. In order to detect and quantify the Nocardia sp. H17-1 in soil samples, we quantified the genes encoding 16S ribosomal RNA(16S rRNA), alkane monooxygenase(alkB4), and catechol 2,3-dioxygenase(23CAT) with real-time PCR using SYBR green. The amounts of H17-1 16S rRNA and alkB4 detected increased rapidly up to 1,000-folds for the first 10 days, and then continued to increase only slightly or leveled off. However, the abundance of the 23CAT gene detected in H17-1-treated soil, where H17-1 had neither the 23CAT gene for the degradation of aromatic hydrocarbons nor the catechol 2,3-dioxygenase activity, did not differ significantly from that of the untreated soil($\alpha$=0.05,p>0.22). These results indicated that H17-1 is a potential candidate for the bioaugmentation of alkane-contaminated soil. Overall, we evaluated the abundance and metabolic activity of the bioremediation strain H17-1 using real-time PCR, independent of cultivation.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.54-63
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• 2015

Increasing air pollution levels and the global oil crisis has become a major hindrance in the growth of our automobile sector. Traditional Internal Combustion engines running on non-renewable fuels are proving to be the major culprit for the harmful effects on environment. With few modifications and also with assistance of few additional components current small SI engines can be modified into a pneumatic engine (commonly known as Compressed Air Engines) without much technical complications where the working fluid is compressed air. The working principle is very basic as adiabatic expansion of the compressed air takes place inside the cylinder pushing the piston downwards creating enough MEP to run the crank shaft at decent RPM. With the assistance of new research and development on pneumatic engines can explore the potential of pneumatic engines as a viable option over IC engines. The paper deals with analysis on RPM variation with corresponding compressed air injection at different crank angles from TDC keeping constant injection time period. Similarly RPM variation can also be observed at different injection pressures with similar injection angle variation. A setup employing a combination of magnetic switch (reed switch), magnets and solenoid valve is used in order to injection timing control. A conclusive data is obtained after detailed analysis of RPM variation that can be employed in newly modified pneumatic engines in order to enhance the running performance. With a number of benefits offered by pneumatic engine over IC engines such as no emissions, better efficiency, low running cost, light weight accompanied by optimized injection conditions can cause a significant development in pneumatic engines without any major alteration.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.219-225
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• 2015

The primary step for efficient control of viral diseases is the development of simple, rapid, and sensitive virus detection. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) has been used to detect viral RNA molecules because of its simplicity and high sensitivity for a number of viruses. RT-LAMP for the detection of Potato virus X (PVX) was developed and compared with conventional reverse transcription polymerase chain reaction (RT-PCR) to demonstrate its advantages over RT-PCR. RT-LAMP reactions were conducted with or without a set of loop primers since one out of six primers showed PVX specificity. Based on real-time monitoring, RT-LAMP detected PVX around 30 min, compared to 120 min for RT-PCR. By adding a fluorescent reagent during the reaction, the extra step of visualization by gel electrophoresis was not necessary. RT-LAMP was conducted using simple inexpensive instruments and a regular incubator to evaluate whether RNA could be amplified at a constant temperature instead of using an expensive thermal cycler. This study shows the potential of RT-LAMP for the diagnosis of viral diseases and PVX epidemiology because of its simplicity and rapidness compared to RT-PCR.

• Journal of Microbiology and Biotechnology
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• v.21 no.1
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• pp.71-80
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• 2011

Four diazinon-degrading bacteria were isolated from agricultural soil by using an enrichment technique. The biochemical analysis and molecular method including RFLP indicated that these isolates were identical, and one strain designated DI101 was selected for further study. Phylogenetic analysis based on 16S rDNA sequencing indicated that the strain DI101 clearly belongs to the Serratia marcescens group. The ability of the strain to utilize diazinon as a source of carbon and phosphorus was investigated under different culture conditions. The DI101 strain was able to completely degrade 50 mg/l diazinon in MSM within 11 days with a degradation rate of 0.226 $day^{-1}$. The inoculation of sterilized soil treated with 100 mg/kg of diazinon with $10^6$ CFU/g DI101 resulted in a faster degradation rate than was recorded in non-sterilized soil. The diazinon degradation rate by DI101 was efficient at temperatures from 25 to $30^{\circ}C$ and at pHs from 7.0 to 8.0. The degradation rate of diazinon was not affected by the absence of a phosphorus supplement, and addition of other carbon sources (glucose or succinate) resulted in the slowing down of the degradation rate. The maximum degradation rate ($V_{max}$) of diazinon was 0.292 $day^{-1}$ and its saturation constant ($K_s$) was 11 mg/l, as determined by a Michaelis-Menten curve. The strain was able to degrade diethylthiophosphate-containing organophosphates such as chlorpyrifos, coumaphos, parathion, and isazofos when provided as a source of carbon and phosphorus, but not ethoprophos, cadusafos, and fenamiphos. These results propose useful information for the potential application of the DI101 strain in bioremediation of pesticide-contaminated environments.

• Journal of Nutrition and Health
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• v.44 no.6
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• pp.474-480
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• 2011

Calcium (Ca) is an essential element to maintain body homeostasis. However, many factors disturb calcium absorption. Aspartic acid chelated calcium (AAC) was synthesized by new methods using calcium carbonate and aspartic acid. This study was carried out to investigate the bioavailability of AAC in Ca-deficient rats. The experimental groups were as follows: NC; normal diet control group, CD-C; untreated control group of Ca-deficient (CD) rats, CD-$CaCO_3$; $CaCO_3$ treated group of CD rats, CD-AAC; AAC treated group of CD rats, and CD-SWC; and seaweed-derived Ca treated group of CD rats. The Ca content of various types of Ca was held constant at 32 mg/day, and the four CD groups were fed for 7 days after randomized grouping. Ca content in serum, urine, and feces within feeding periods were analyzed to confirm Ca absorption. Serum Ca content was significantly higher in the CD-AAC (11.24 mg/dL) and CD-SWC (10.12 mg/dL) groups than that in the CD-C (8.6 mg/dL) group 2 hours following the first administration. The Ca content in feces was significantly lower in the CD-AAC (35.4 mg/3 days) and CD-SWC (71.1 mg/3 day) groups than that in the CD-$CaCO_3$ (98.7 mg/3 days) group (p > 0.05). AAC had a 2.3-fold higher absorption rate of Ca than that of SWC. No differences in fibula length were observed in the NC and CD groups. The fibula weights of the CD-AAC (0.33 g) and CD-SWC (0.33 g) groups increased compared to those in the CD-C (0.27 g) group; however, no significant difference was observed between the CD groups. We conclude that bioavailability of AAC is higher than that of seaweed-derived Ca or inorganic Ca. Thus, these findings suggest the AAC has potential as a functional food material related to Ca metabolism.