• Analytical Science and Technology
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• v.20 no.1
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• pp.25-32
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• 2007

The measurement methods for total nitrogen in wastewater containing a high concentration of nitrogen were evaluated. (1) The UV spectrophotometry, (2) reduction-distillation Kjeldahl, (3) total Kjeldahl nitrogen, and (4) ion chromatography methods were applied. The experimental procedure of the UV spectrophotometric method was simple, but it produced large errors deriving from the dilution of samples and calibration standards. While, the reduction-distillation Kjeldahl method didn't need dilution, but the amount of Devarda's alloy and NaOH lead to large errors up to 50 mg/L. The levels of total nitrogen measured by each method were as follows: reduction-distillation Kjeldahl ($568.6{\pm}38.7mg/L$) > UV spectrophotometry ($527.3{\pm}9.6mg/L$) > total Kjeldahl nitrogen method ($494.7{\pm}21.4mg/L$) > ion chromatography method ($417.9{\pm}7.3mg/L$). Therefore, the reduction-distillation Kjeldahl method is preferred for wastewater with the high concentration of nitrogen. Optimal conditions for each experimental procedure, however, are needed to be confirmed, and the Standard Operation Procedure (SOP) for total nitrogen is required for reliable measurements.

• Korean Journal of Pharmacognosy
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• v.46 no.4
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• pp.279-282
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• 2015

In order to quantify compound K(CK), anticancer component of Panax ginseng C. A. Meyer, high titer rabbit polyclonal antibodies (pAbs) were raised against a conjugate of CK and bovine serum albumin coupled by a periodate oxidation method. Coating antigen (CK-OVA) was also prepared by the same method with OVA. As a result of optimization of antiserum dilution (2,000 fold), coating antigen ($25{\mu}g/ml$) and other condition (incubation time, temperature and washing method), ELISA method for the determination of CK was established. The measuring range extended from 0.5 ng/ml to 25 ng/ml of CK. The antibodies exhibited minor or even no cross reactivities with protopanaxatriol (1.56%) and other tested ginsenosides, $GRb_1$ (0.11%), $GRg_1$ (0.07%) except protopanaxadiol (87.2%) from the structural similarity. And the antibody showed good correlation (r=0.987) between the assay values obtained by this ELISA method and HPLC. Therefore, the ELISA method could be very useful tools for the determination of CK in biological fluids because of their high sensitivity and specificity.

• YAKHAK HOEJI
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• v.43 no.5
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• pp.606-613
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• 1999

To survey the possibility of replacing the pyrogen test with Limulus Amebocyte Lysate(LAL) test and to find out a standard methods suitable to our blood products made in Korea, 100 samples of 20% human serum albumin were tested by commercial LAL test kits and results of those were compared with rabbit pyrogen test. The LAL test is used both dinetic-chromogenically and kinetic-turbidimetrically. Both methods equally showed broad detection range (5.0~0.005 EU/ml), excellent sensitivity ($\geq$ 0.005 EU/ml) and predominant recovery rate within valid dilution range, but kinetic-turbidimetric method seemed to be more reproducible than kinetic-chromogenic method(kinetic-chromogenic method : S.D. = 15.88, kinetic-turbidimetric method : S.D. = 8.12). After heating the sample at 75$^{\circ}C$ for 15 min, the results showed a little elevated recovery rate with both methods. After performing the test on 100 albumin samples with both kits, the results were analysed using the USP standard (1.33 EU/ml). 7% of samples in kinetic-chromogenic methods and 1% of samples in kinetic-turbidimetric method exceeded the limit of endotoxin levels regulated for blood products in USA. Because this phenomenon was not observed in both methods at the same time and both methods have high sensitivity ($\geq$0.005 EU/ml), these results seemed to depend on nonspecific reaction. Considering its sensitivity and reproducibility, we could assure that LAL test is proper to detecting pyrogenic with good sensitivity.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.1
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• pp.11-22
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• 2023

In this paper, we propose an efficient satellite selection method for multi-constellation GNSS. The number of visible satellites has increased dramatically recently due to multi-constellation GNSS. By the increased availability, the overall GNSS performance can be improved. Whereas, due to the increase of the number of visible satellites, the computational burden in implementing advanced processing such as integer ambiguity resolution and fault detection can be increased considerably. As widely known, the optimal satellite selection method requires very large computational burden and its real-time implementation is practically impossible. To reduce computational burden, several sub-optimal but efficient satellite selection methods have been proposed recently. However, these methods are prone to the local optimum problem and do not fully utilize the information redundancy between different constellation systems. To solve this problem, the proposed method utilizes the inter-system biases and geometric assignments. As a result, the proposed method can be implemented in real-time, avoids the local optimum problem, and does not exclude any single-satellite constellation. The performance of the proposed method is compared with the optimal method and two popular sub-optimal methods by a simulation and an experiment.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.701-710
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• 2004

Uncertainty was quantified to evaluate calcium determination result in infant formula with AAS (Atomic Absorption Spectrometry) and ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Uncertainty sources in measurand, such as sample weight, final volume of sample, sample dilution and the instrumental result were identified and used as parameters for combined standard uncertainty based on the GUM (Guide to the expression of uncertainty in measurement) and Draft EURACHEM/CITAC Guide. Uncertainty components of each sources in measurand were identified as resolution, reproducibility and stability of chemical balance, standard material purity, standard material molecular weight, standard solution concentration, standard solution dilution factor, sample dilution factor, calibration curve, recovery, instrumental precision, reproducibility, and stability, Each uncertainty components were evaluated by uncertainty types and included to calculate combined uncertainty. The kinds of uncertainty sources and components in the analytical method by AAS and ICP-AES were same except sample dilution factor for AAS. The analytical results and combined standard uncertainties of calcium content were estimated within the certification range $(367{\pm}20\;mg/100g)$ of CRM (Certified Reference Material) and were not significantly different between method by AAS followed by ashing and method by ICP-AES followed by acid digestion as $359.52{\pm}23.61\;mg/100g\;and\;354.75{\pm}16.16\;mg/100g$, respectively. Identifying uncertainty sources related with precision, repeatability, stability, and maintaining proper instrumental conditions as well as personal proficiency was needed to reduce analytical error.

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.141-147
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• 2013

The purpose of this study was attempted to new methods in mammalian embryos vitrification. This method was affected to increase of the embryo vitrification efficiency and it would be applied to the field of embryo transfer to recipient by modified loading method of embryo into 0.25 ml plastic straw. The frozen mouse embryos were carried out warmed from two different cell stages (8-cell and blastocyst, respectively) by attachment of an embryo in the vitrification straw (aV) method. All groups were cultured in M-16 medium to determine the development and survivability for 24 h, respectively. Results shown that, the survivability of two different groups were significantly different (94.8% vs. 70.9%). Total cell number was not significantly different the non-frozen blastocyst ($99.7{\pm}12.4$) compared to the post-thaw blastocyst ($94.8{\pm}15.1$). From the 8-cell embryo, total cell number of frozen blastocysts were significantly lower than others groups ($74.7{\pm}14.6$, p<0.05). In the case of cell death analysis, the blastocysts from non-frozen and frozen-thawed 8-cell group were not different ($0.0{\pm}0.0$ vs. $1.9{\pm}3.1$, p>0.05). However, the apoptotic nuclei of blastocyst were significantly observed the frozen-thawed group ($5.4{\pm}4.4$) compared to non-frozen group (p<0.05). Therefore, this new method of embryos using in-straw dilution and direct transfer into other species would be more simple procedure of embryo transfer rather than step-wise dilution method and cryopreservation vessels, so we can be applied in animal as well as human embryo cryopreservation in further.

• Analytical Science and Technology
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• v.29 no.5
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• pp.234-241
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• 2016

The approach presented in this article refers to the bioanalytical method validation for the detection and quantitative determination of arsenic species including arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) in dog plasma by high-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP/MS). The arsenic species were separated using an agilent As speciation column by a mobile phase of 2 mM sodium phosphate monobasic, 0.2 mM ethylenediaminetetraacetic acid disodium salt dehydrate, 10 mM sodium acetate, 3 mM sodium nitrate and 1 % ethyl alcohol at pH 11 (adjusted with 1M NaOH). The method validation experiment was obtained selectivity, linearity, accuracy, precision, matrix effect, recovery, system suitability, dilution integrity and various stabilities. All calibration curves showed good linearity (R²>0.999) within test ranges. The lower limit of quantitation (LLOQ) was 5 ng/mL for As(III), As(V) and DMA, and 20 ng/mL for MMA. The system suitability and dilution values were within 6.5 % and 7.7 %. Subsequently, the developed and validated HPLC-ICP/MS method was also successfully applied to determine the arsenic speciation in dog plasma samples, and the recoveries for the spiked samples were in the range of 91.5–102.2 %. Therefore, this method could be applied to the evaluation of arsenic exposure, health effect assessment and other bio-monitoring studies in biological samples.

• Journal of Mushroom
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• v.9 no.3
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• pp.110-115
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• 2011

Trichoderma disease of oyster mushroom has not been effectively detected in the field for testing its resistance against the disease with its varieties. In this study, we investigated the methods to detect its resistance in the laboratory by using media, which enables us to understand the relevant characteristics (e.g., lysis, toxin enzyme, mycelial growth rate). In coculturing with strains of Trichoderma and oyster mushroom, it is possible to observe the difference in the resistance of oyster mushroom against Trichoderma with the phenomena of barrage reaction, overgrowth and lysis. We also observed the inhibition of mycelial growth of oyster mushroom using the dilution method with 48-well plate, but could not observed the inhibition of mycelial growth using the filter paper method of cultural supernatant. In simultaneously culturing both Trichoderma and oyster mushroom, it was possible to detect the inhibition of the mycelial growth of oyster mushroom, but Trichoderma mycelium did not overgrow against oyster mushroom. We found that the pathogenicity was efficient in using solid medium with the phenomena of overgrowth and lysis by inoculating Trichoderma on top of mycelia of oyster mushroom. In conclusion, the methods (e.g., coculture method, dilution method with 48-well plate, post-inoculation method) are recommended to detect the resistance of oyster mushroom against Trichoderma disease.

• The Journal of the Korean Society for Microbiology
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• v.5 no.1
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• pp.27-31
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• 1970

Nalidixic acid and six other drugs were studied for in vitro effectiveness against 200 strains of Escherichia coli isolated recently from healthy persons and bactericidal activity of ampicillin against one respective strain of Escherichia coli and Salmonella typhi isolated were also studied. The resutlts obtained by the plate dilution method showed the following percentage of resistance: kanamycin, 2.5%; streptomycin, 12.0%; ampicillin, 13.5%; tetracyclin, 15.5%; chloramphenicol, 17.5%; colistin sulfate, 19.5%. No strains were resistant to nalidixic acid, clearly indicating that nalidixic acid is the most effective drug tested. Ampicillin, measured by test-tube diltion method, was highly bactericidal against Salmonella typhi at the concentration of 2.5mcg/ml and against Escherichia coli at 5mcg/ml.

• Parasites, Hosts and Diseases
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• v.34 no.3
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• pp.211-213
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• 1996

Malaysian, Ajricn and Thai PZQsmodiumJnkipamm isolates were cultured in uiko by the Tracer and Jensen method (1976, 1977) and were later cloned by the limiting dilution method (Rosario, 1981), Forty-eight clones were obtained and were characterized by electrophoretic variations of GDH (NADP-dependent glutamate dehydrogenase)(EC. 1.4.1.4). It was found that they were pure clones because they possessed either GDH-1 or GDH-2 unlike their parent isolates which exhibited both GDH-1 and GDH-2.