• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1181-1187
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• 2003

Condensation of 4-cyano-5,6-dimethyl-3-pyridazinone 1 with aromatic aldehydes gave the novel styryl derivatives 2a-c. Refluxing of compound 2a with phosphorus oxychloride furnished 3-chloropyridazine derivative 3. Compound 3 was reacted with thiourea and produced pyridazine-3(2H)thione 4. Thieno[2,3-c]- pyridazines 5a-e were achieved by cycloalkylation of compound 4 with halocompounds in methanol under reflux and in the presence of sodium methoxide. Also, refluxing of compound 4 with N-substituted chloroacetamide in the presence of potassium carbonate afforded thienopyridazines 6a-e. Cyclization of compound 6 with some electrophilic reagents as carbon disulfide and triethyl orthoformate furnished the novel pyrimido[4',5':4,5]thieno[2,3-c]pyridazines 12 and 13a-c, respectively. Diazotisation of compound 6 with sodium nitrite in acetic acid produced the pyridazino[4',3':4,5]thieno[3,2-d][1,2,3]triazines 14a-c. Ternary condensation of compound 1, aromatic aldehydes and malononitrile in ethanol containing piperidine under reflux afforded the novel phthalazines 16a-c. Compound 3 was subjected to some nucleophilic substitution reactions with amines and sodium azide and formed the aminopyridazines 17a, b and tetrazolo[1,5-b]-pyridazine 19, respectively. The structures of the synthesized compounds were established by elemental and spectral analyses.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1254-1254
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• 2001

Near infrared spectroscopy (NIRS) was applied to determination of the lipid content of compost during compost fermentation of tofu(soybean-curd) refuse. The reflected rays in the wavelength range between 800 and 2500 nm were measured at 2 nm intervals. The absorption of lipid observed at 4 wavelengths, 1208, 1712, 2312 and 2352 nm on the second derivative spectra. To formulate a calibration equation, a multiple linear regression analysis was carried out between the near-infrared spectral data and on the lipid content in the calibration sample set (sample number, n=60) obtained using a Soxhlet extraction method. The calibration equation for prediction of lipid, the value of the multiple correlation coefficient (R) was 0.975 when using the wavelengths of 1208 and 1712nm. To validate the calibration equation obtained, the lipid content in the validation sample set (n=35) not used for formulating the calibration equation were calculated using the calibration equations, and compared with the values obtained using the Soxhlet extraction method. Good agreement were observed between the results of the Soxhlet extraction method and those values of the NIRS method. The simple correlation coefficient (r) and standard error of prediction (SEP) were 0.964 and 0.815 %, respectively. Then, the NIRS method was applied to a compost fermentation in which the time course the lipid content were measured and good results were obtained. The study indicates that NIRS is a useful method for process management of the compost fermentation of tofu refuse.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1157-1157
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• 2001

Yeast, Kurtzurnanomyces sp. I-11, produces biosurfactant, mannosyl erythritol lipid (MEL), from soya oil. The properties of biosurfactant MEL include low-toxicity and high biodegradability. MEL provides new possibilities for a wide range of industrial applications, especially food, cosmetic, pharmaceutical fields and chemicals for biotechnology. In the fermentation process, techniques of measuring and controlling substrates and products are important to obtain high productivity with optimum concentrations of substrate and product in the culture broth. The measurement system for the concentrations of soya oil and MEL in the fermentation process was developed using near-infrared spectroscopy (NIRS). Soya oil and MEL in the culture broth were extracted with ethyl acetate and NIR spectra was carried out between the second derivative NIR spectral data at 1312 and 2040 nm and MEL concentrations obtained using a thin-layer chromatography with a flame-ionization detector (TLC/FID) method. A calibration equation for soya oil was results of the validation of the calibration equation, good agreement was observed between the results of the TLD/FID method and those of the NIRS method for both constituents. NIR method was applied to the measurement of the concentrations of MEL and soya oil in the practical fermentation and good results were obtained. The study indicates that NIRS is a useful method for measurement of the substrate and product in the glycolipid fermentation.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1154-1154
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• 2001

Near infra-red (NIR) spectroscopy has been used for the non-invasive assessment of intact fruit for eating quality attributes such as total soluble solids (TSS) content. However, little information is available in the literature with respect to the robustness of such calibration models validated against independent populations (however, see Peiris et al. 1998 and Guthrie et al. 1998). Many studies report ‘prediction’ statistics in which the calibration and prediction sets are subsets of the same population (e. g. a three year calibration validated against a set from the same population, Peiris et al. 1998; calibration and validation subsets of the same initial population, Guthrie and Walsh 1997 and McGlone and Kawano 1998). In this study, a calibration was developed across 84 melon fruit (R$^2$= 0.86$^{\circ}$Brix, SECV = 0.38$^{\circ}$Brix), which predicted well on fruit excluded from the calibration set but taken from the same population (n = 24, SEP = 0.38$^{\circ}$Brix with 0.1$^{\circ}$Brix bias), relative to an independent group (same variety and farm but different harvest date) (n = 24, SEP= 0.66$^{\circ}$ Brix with 0.1$^{\circ}$Brix bias). Prediction on a different variety, different growing district and time was worse (n = 24, SEP = 1.2$^{\circ}$Brix with 0.9$^{\circ}$Brix bias). Using an ‘in-line’ unit based on a silicon diode array spectrometer, as described in Walsh et al. (2000), we collected spectra from fruit populations covering different varieties, growing districts and time. The calibration procedure was optimized in terms of spectral window, derivative function and scatter correction. Performance of a calibration across new populations of fruit (different varieties, growing districts and harvest date) is reported. Various calibration sample selection techniques (primarily based on Mahalanobis distances), were trialled to structure the calibration population to improve robustness of prediction on independent sets. Optimization of calibration population structure (using the ISI protocols of neighbourhood and global distances) resulted in the elimination of over 50% of the initial data set. The use of the ISI Local Calibration routine was also investigated.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1346-1353
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• 2014

In the present study, an anthraquinone derivative, questinol was successfully isolated from the broth extract of the marine-derived fungus Eurotium amstelodami for the first time. The structure of questinol was determined based on the analysis of the MS and NMR spectral data as well as comparison of those data with the published data. Moreover, the anti-inflammatory effect of questinol in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells was investigated. The results showed that questinol did not exhibit cytotoxicity in LPS-stimulated RAW 264.7 cells up to $200{\mu}M$. Questinol could significantly inhibit NO and $PGE_2$ production at indicated concentrations. Questinol was also found to inhibit the production of pro-inflammatory cytokines, including TNF-${\alpha}$, IL-1${\beta}$, and IL-6. Furthermore, the western blot analysis showed that questinol suppressed the expression level of iNOS in a dose-dependent manner. However, questinol could slightly inhibit the expression of COX-2 at the concentration of $200{\mu}M$. Therefore, our study suggests that questinol might be selected as a promising agent for the prevention and therapy of inflammatory disease.

• Smart Structures and Systems
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• v.19 no.5
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• pp.487-497
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• 2017

Semi-active devices use the building's own motion to produce resistive forces and are thus strictly dissipative and require little power. Devices that independently control the binary open/closed valve state can enable novel device hysteresis loops that were not previously possible. However, some device hysteresis loops cannot be obtained without active analog valve control allowing slower, controlled release of stored energy, and is presents an ongoing limitation in obtaining the full range of possibilities offered by these devices. This in silico study develops a proportional-derivative feedback control law using a validated nonlinear device model to track an ideal diamond-shaped force-displacement response profile using active analog valve control. It is validated by comparison to the ideal shape for both sinusoidal and random seismic input motions. Structural application specific spectral analysis compares the performance for the non-linear, actively controlled case to those obtained with an ideal, linear model to validate that the potential performance will be retained when considering realistic nonlinear behaviour and the designed valve control approach. Results show tracking of the device force-displacement loop to within 3-5% of the desired ideal curve. Valve delay, rather than control law design, is the primary limiting factor, and analysis indicates a ratio of valve delay to structural period must be 1/10 or smaller to ensure adequate tracking, relating valve performance to structural period and overall device performance under control. Overall, the results show that active analog feedback control of energy release in these devices can significantly increase the range of resetable, valve-controlled semi-active device performance and hysteresis loops, in turn increasing their performance envelop and application space.

• Near Infrared Analysis
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• v.1 no.2
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• pp.21-27
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• 2000

Temperature-dependent changes in near-infrared (NIR) spectra have been measured for oleic acid, and nonanoic acid in the pure liquid state. Particular attention has been paid to the 5400-4800 cm$\^$-1/ region where a number of combination bands appear. The NIR spectra of oleic acid show that a band at 5303 cm$\^$-1/ increases with temperature while that at 5270 cm/sup-1/ decreases. It ha been found from their second derivative spectra that these spectral changes take place stepwisely with two break points at 30 and 53$\^{C}$, which correspond to the phase transition temperatures oleic acid reported previously. Principle component analysis (PCA) has been carried out for the NIR spectra of oleic acid in the 5400-4800 cm$\^$-1/ region measured over a temperature range of 15-80$\^{C}$. core plots of the first and second principal components (PCs) show that the NIR spectra are classified into three groups; the spectra measured in the temperature range of 15-30$\^{C}$, those in the range of 31-53$\^{C}$, and those in the range of 54-80$\^{C}$. These temperature ranges correspond to those for quasi-smectic liquid crystal, disordered liquid crystal, and isotropic liquid of oleic acid in the pure liquid state. In other words, PCA provides unambiguous evidence for the phase transitions. similar studies have been carried out for petroselinic acid and nonanoic acid in the pure liquid states, but they do not show any evidence for phase transitions.

• Journal of the Korean Chemical Society
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• v.22 no.4
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• pp.239-244
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• 1978

Spectroscopic studies of trans-1,2-bispyrazylethylene (BPE), one of the stilbene analogues, were carried out. In normal UV spectra, a distinct $n{\rightarrow}{\pi}^*$ absorption band is missing because of a strong, nearly isoenergetic ${\pi}{\rightarrow}{\pi}^*$ absorption band. The second derivative and low temperature $(77^{\circ}K)$ UV absorption spectra were taken and $n{\rightarrow}{\pi}^*$ absorption band was identified by these methods. The transition energies of ${\pi}{\rightarrow}{\pi}^*$ transitions were calculated by Pariser-Parr-Pople (PPP)-SCF-CI MO method. The calculated values showed good agreement with the observed spectral data. Luminescence studies were also carried out at low temperature. From the fluorescence spectra, fluorescence polarization studies, and PPP-SCF-CI MO calculation, the fluorescent state was determined to be a singlet $({\pi},\;{\pi}^*)$ state. This conclusion is in good agreement with the results obtained from alkaline salt effects on the fluorescence of this compound.

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.184-191
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• 1994

A zearalenone derivative, methyldihydroxyzearalenone has been isolated from a plant pathogenic fungus, Drechslera portulacae which causes necrosis on the leaves and stem of Portulaca oleracea. It was characterized as 3, 4, 5, 6, 9, 10-hexahydro-8, 9, 16-trihydroxy-14-methoxy-3-methyl-1H-2-benzoxacyclotetradecine-1, 7(8H)-dione on the basis of spectral analysis. Methyldihydroxyzearalenone treatment at $3{\times}10^{-5}M$ inhibited root length of Echinochloa crus-galli and Abutilon avicennae by 35.7% and 72.6% as compared with the control, respectively.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.633-644
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• 2020

Rice paper is an element of Vietnamese cuisine that can be used to wrap vegetables and meat. Rice and starch are the main ingredients of rice paper and their mixing ratio is important for quality control. In a commercial factory, assessment of food safety and quantitative supply is a challenging issue. A rapid and non-destructive monitoring system is therefore necessary in commercial production systems to ensure the food safety of rice and starch flour for the rice paper wrap. In this study, fluorescence hyperspectral imaging technology was applied to classify grain flours. Using the 3D hyper cube of fluorescence hyperspectral imaging (fHSI, 420 - 730 nm), spectral and spatial data and chemometric methods were applied to detect and classify flours. Eight flours (rice: 4, starch: 4) were prepared and hyperspectral images were acquired in a 5 (L) × 5 (W) × 1.5 (H) cm container. Linear discriminant analysis (LDA), partial least square discriminant analysis (PLSDA), support vector machine (SVM), classification and regression tree (CART), and random forest (RF) with a few preprocessing methods (multivariate scatter correction [MSC], 1^st and 2^nd derivative and moving average) were applied to classify grain flours and the accuracy was compared using a confusion matrix (accuracy and kappa coefficient). LDA with moving average showed the highest accuracy at A = 0.9362 (K = 0.9270). 1D convolutional neural network (CNN) demonstrated a classification result of A = 0.94 and showed improved classification results between mimyeon flour (MF)1 and MF2 of 0.72 and 0.87, respectively. In this study, the potential of non-destructive detection and classification of grain flours using fHSI technology and machine learning methods was demonstrated.