• Korean journal of applied entomology
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• v.50 no.2
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• pp.107-113
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• 2011

Benzylideneacetone (BZA) is a compound derived from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila (Xn). Its immunosuppressive activity is caused by its inhibitory activity against eicosanoid biosynthesis. This BZA is being developed as an additive to enhance control efficacy of other commercial microbial insecticides. This study was focused on the enhancement of the immunosuppressive activity of BZA by generating its chemical derivatives toward decrease of its hydrophobicity. Two hydroxylated BZA and one sugar-conjugated BZA were chemically synthesized. All derivatives had the inhibitory activities of BZA against phospholipase $A_2$ ($PLA_2$) and phenoloxidase (PO) of the diamondback moth, Plutella xylostella, but BZA was the most potent. Mixtures of any BZA derivative with Bacillus thuringiensis (Bt) significantly increased pathogenicity of Bt. BZA also inhibited colony growth of four plant pathogenic fungi. However, BZA derivatives (especially the sugar-conjugated BZA) lost the antifungal activity. These results indicated that BZA and its derivatives inhibited catalytic activities of two immune-associated enzymes ($PLA_2$ and PO) of P. xylostella and enhanced Bt pathogenicity. We suggest its use to control plant pathogenic fungi.

• The Korean Journal of Pesticide Science
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• v.8 no.2
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• pp.137-144
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• 2004

[ $\beta$ ]-Ketoacetoanilide chloride derivatives containing a substituent at 4 in phenyl group (para) reduced specifically the development of tomato late blight caused by Phytophthora infestans. Among $\beta$ketoacetoanilide chloride derivatives, five (KIST163, KIST170, KIST260, KIST263, and KIST267) were selected and tested for their protective, curative, systemic, persistent activities, and disease control efficacy against tomato late blight on adult plants. They exhibited a strong l-day protective activity and $EC_{50}$ of KIST163 and KIST170 were 21.9 and $14.5{\mu}g/mL$, respectively. However, they had little curative and systemic activities. Good persistence of KIST163 and KIST170 on tomato plants were observed against P. infestans; both KIST163 and KIST170 at $100{\mu}g/mL$ showed control values more than 75% in a 7-day protective applications. In addition, the two chemicals effectively controlled the occurrence of P. infestans on adult tomato plants. These results indicate that five $\beta$-ketoacetoanilide chloride derivatives are foliar fungicides with a preventive action and KIST163 and KIST170 have a potential for the control of tomato late blight in the fields.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1871-1876
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• 2005

In this paper, We present a new nonlinear adaptive control law using a disturbance accommodating control (DAC) observer for a Japanese automatic landing flight experiment vehicle called ALFLEX. A future spaceplane must have ability to deal with greater fluctuations in the stability and control derivatives of flight dynamics, because its flight region is much wider than that of conventional aircraft. In our previous studies, digital adaptive flight control systems have been developed based on a linear-parameter-varying (LPV) model depending on dynamic pressure, and obtained good simulation results. However, under previous control laws, it is difficult to accommodate uncertainties represented by disturbance and nonlinearity, and to design a stable flight control system. Therefore, in this study, we attempted to design a nonlinear adaptive control law using the DAC Observer and inverse dynamic methods. A good tracking property of the obtained system was confirmed in numerical simulation.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.127-133
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• 1995

A Series of meta and para-substituted phenyl N-methylcarbamate derivatives were synthesized and influence of substituents(X) on the molecular orbital(MO) quantities of carbonyl group, carbamylation reaction center, and insecticidal activities($pI_50$) were discussed quantitatively. From these findings, the most stable streo conformer(Z) shows that the planer phenyl group occupies vertical(${\theta}=90^{\circ}$) position on the plane of the N-methylcarbamyl group. The carbamylation mechanism was proposed that the carbamylation process of acetylcholinesterase(ACh.E) by m-methyl substituted phenyl N-methylcarbamate derivatives proceeds via hyperconjugation of m-methyl group and carbonyl oxygene protonation, theromodynamically control reaction with acidic site of ACh.E.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.314-321
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• 2008

Acaricidal effects of materials derived from Diospyros kaki roots against Dermatophagoides farinae and D. pteronyssinus were assessed using impregnated fabric disk bioassay and compared with that of the commercial benzyl benzoate. The observed responses varied according to dosage and mite species. The $LD_{50}$ values of the chloroform extract of Diospyros kaki roots were 1.66 and $0.96{\mu}g/cm^2$ against D. farinae and D. pteronyssinus. The chloroform extract of Diospyros kaki roots was approximately 15.2 more toxic than benzyl benzoate against D. farinae, and 7.6 times more toxic against D. pteronyssinus. Purification of the biologically active constituent from D. kaki roots was done by using silica gel chromatography and high-performance liquid chromatography. The structure of the acaricidal component was analyzed by GC-MS, $^1H-NMR,\;^{13}C-NMR,\;^1H-^{13}C$ COSY-NMR, and DEPT-NMR spectra, and identified as plumbagin. The acaricidal activity of plumbagin and its derivatives (naphthazarin, dichlon, 2,3-dibromo-1,4-naphthoquinone, and 2-bromo-1,4-naphthoquinone) was examined. On the basis of $LD_{50}$ values, the most toxic compound against D. farinae was naphthazarin $(0.011{\mu}g/cm^2)$ followed by plumbagin $(0.019{\mu}g/cm^2),$ 2-bromo-1,4-naphthoquinone $(0.079{\mu}g/cm^2)$, dichlon $(0.422{\mu}g/cm^2)$, and benzyl benzoate $(9.14{\mu}g/cm^2)$. Additionally, the skin color of the dust mites was changed from colorless-transparent to dark brown-black by the treatment of plumbagin. Similar results have been exhibited in its derivatives (naphthazarin, dichlon, and 2-bromo-1,4-naphthoquinone). In contrast, little or no discoloration was observed for benzyl benzoate. From this point of view, plumbagin and its derivatives can be very useful for the potential control agents, lead compounds, and indicator of house dust mites.

• Journal of Navigation and Port Research
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• v.38 no.2
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• pp.97-103
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• 2014

In these days, the world has been increasing navy forces such as aircraft carriers and high-tech destroyers etc. and the importance of submarines is being emphasized. Therefore, accurate values of the derivatives in equations of motion are required to control motion of the submarines. Hydrodynamic derivatives were measured by the vertical planar motion mechanism(VPMM) model test. VPMM equipment gave pure heave and pitch motion respectively to the submarine model and the forces and moments were acquired by load cells. As a result, the hydrodynamic derivatives of the submarine are provided through the Fourier analysis of the forces and moments in this paper.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.27-33
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• 2000

N-Dimethoxyphosphinothionyl carbofuran, PSC, has a high insecticidal activity and low mammalian toxicity. Ten N-phosphinothionyl carbofuran derivatives were synthesized and their insecticidal activities were determined against brown plant hopper (Nilaparvata lugens), green peach aphid (Myzus persicae), diamondback moth (Plutella xylostella), and two-spotted spider mite (Tetranychus urticae). Green peach aphid, diamondback mea and brown plant hopper were controlled over 90% by application of 125 ppm, 125 ppm, and 63 ppm, respectively, of carbosulfan. Two hundred and fifty ppm of newly synthesized compounds could control most of brown plant hopper and diamondback moth. Especially, insecticidal activities of compound 10 against brown plant hopper, diamondback moth, and green peach aphid were similar to those of carbosulfan. Our results show that the newly synthesized derivatives of NV-phosphinothionyl carbofuran have a similar insecticidal activity to carbosulfan.

• The Korean Journal of Pain
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• v.35 no.4
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• pp.440-446
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• 2022

Background: The authors showed in a previous study that some novel triazine derivatives had an anti-inflammatory effect. The present study was designed to evaluate the antinociceptive effect of five out of nine compounds including two vanillintriazine (5c and 5d) and three phenylpyrazole-triazine (10a, 10b, 10e) derivatives which showed the best anti-inflammatory effect. Methods: Male Swiss mice (25-30 g) were used. To assess the antinociceptive effect, acetic acid-writhing, formalin, and hot plate tests were used after intraperitoneal injection of each compound. Results: All compounds significantly (P < 0.001) reduced acetic acid-induced writhing at tested doses (50, 100, and 200 mg/kg). Also, the percent inhibition of writhing in the acetic acid test showed that at the maximum tested dose of these compounds (200 mg/kg), the order of potencies is as follows: 10b > 10a > 10e > 5d > 5c. In the formalin test, compounds 5d, 10a, and 10e showed an antinociceptive effect in the acute phase and all compounds were effective in the chronic phase. In the hot plate test, compounds 5c, 5d, and 10a demonstrated an antinociceptive effect. Conclusions: The results clearly showed that both vanillin-triazine and phenylpyrazole-triazine derivatives had an antinociceptive effect. Also, some compounds which showed activity in the early phase of formalin test as well as in the hot plate test could control acute pain in addition to chronic or inflammatory pain.

• Parasites, Hosts and Diseases
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• v.60 no.6
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• pp.401-407
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• 2022

Antimalarial drugs play an important role in the control and treatment of malaria, a deadly disease caused by the protozoan parasite Plasmodium spp. The development of novel antimalarial agents effective against drug-resistant malarial parasites is urgently needed. The novel derivatives, SKM13-MeO and SKM13-F, were designed based on an SKM13 template by replacing the phenyl group with electron-donating (-OMe) or electron-withdrawing groups (-F), respectively, to reverse the electron density. A colorimetric assay was used to quantify cytotoxicity, and in vitro inhibition assays were performed on 3 different blood stages (ring, trophozoite, and schizonts) of P. falciparum 3D7 and the ring/mixed stage of D6 strain after synchronization. The in vitro cytotoxicity analysis showed that 2 new SKM13 derivatives reduced the cytotoxicity of the SKM13 template. SKM13 maintained the IC₅₀ at the ring and trophozoite stages but not at the schizont stage. The IC₅₀ values for both the trophozoite stage of P. falciparum 3D7 and ring/mixed stages of D6 demonstrated that 2 SKM13 derivatives had decreased antimalarial efficacy, particularly for the SKM13-F derivative. SKM13 may be comparably effective in ring and trophozoite, and electron-donating groups (-OMe) may be better maintain the antimalarial activity than electron-withdrawing groups (-F) in SKM13 modification.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.12
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• pp.998-1003
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• 2002

As nonholonomic dynamic systems have constraints imposed on motions that are not integrable, i.e., the constraints cannot be written as time derivatives of some functions of generalized coordinates, advanced techniques are needed for their control. In this paper, a sliding mode tracking control for nonholonomic dynamic systems is proposed. By introducing a general scheme of coordinate transformation, the state of nonholonomic systems is mapped into a bounded space and a robust controller for dynamic models of nonholonomic systems with input disturbances is designed using sliding mode control scheme. Simulation results of tacking control for a nonholonomic mobile robot with two actuated wheels are provided to show the effectiveness of the proposed controller.