• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.121-128
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• 2011

I/An electro-hydraulic transmission having advantages of convenience, safety, simple linking and high power, and an electronic control system were designed and fabricated. In this study, characteristics of the control system were investigated through outdoor tests for evaluation of installation of the system on a combine. Major findings were as followings. 1. Experiment for performance evaluation of the control system was conducted on concrete road. With steering lever in neutral position, driving HST swash plate and left/right wheel speed increased in proportion to driving lever angle. In case of steering control, steering swash plate angle changed in proportion to steering lever angle. This should cause increase in outer wheel speed, but it was observed that HST swash plate was controlled toward neutral to maintain the speed before steering. As a result, speed before steering was maintained despite the change in outer wheel speed by steering HST swash plate angle change. 2. It was observed that the HST system enabled steering with outer wheel maintained at constant speeds while inner wheel speed decreased, which was more stable than conventional mechanical links. In addition, for the selected 5 criteria, experiment showed satisfactory results and it was judged that installation on real vehicle would be feasible. 3. The control system showed response property of appropriate forward/reverse movement and lift/right steering, without causing any problems during experiment on concrete. Result of response property experiment on field operation also showed appropriate control over forward/reverse movement and left/right steering.

• Journal of Pharmaceutical Investigation
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• v.41 no.6
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• pp.331-336
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• 2011

The instability of hirsutenone (HST), a potential therapeutic candidate for the treatment of atopic dermatitis (AD) and ovarian carcinoma, is one of the main concerns for the development of drug product. In the present study, aqueous stability of HST was investigated by kinetic analysis, and the effect of several factors covering temperature, nitrogen gas ($N_2$) flushing, and selection of proper antioxidant was compared. Cosolvent system composed of distilled water and methanol (9:1 v/v) was used as a vehicle to dissolve HST at the concentration of $200{\mu}g/mL$. Samples of aqueous solution were prepared under the absence or presence of antioxidants, such as ascorbic acid (AA), sodium edetate (EDTA), and ascorbyl palmitate (AP), and subjected for stability test. The degradation of HST in aqueous solution was followed by the first order kinetics with an extremely short half life of less than a week at room temperature, and was accelerated as the temperature increased. $N_2$ flushing brought a little enhancement in stability compared to control solution, but the effect was insufficient. The addition of AA and EDTA (0.1%) significantly enhanced the stability of HST at $40^{\circ}C$, but the addition of AP (0.01%) was limited due to its water insolubility and revealed no promising result. The stability of HST was increased proportionally by the amount of AA added, showing the difference in degree of stabilization as an order of magnitude. Finally, we conclude that HST was stabilized by the addition of a suitable antioxidant, suggesting AA as the most effective stabilizer.

• Biomolecules & Therapeutics
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• v.30 no.6
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• pp.553-561
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• 2022

Chronic myeloid leukemia (CML) is a slowly progressing hematopoietic cell disorder. Sphingosine kinase 1 (SPHK1) plays established roles in tumor initiation, progression, and chemotherapy resistance in a wide range of cancers, including leukemia. However, small-molecule inhibitors targeting SPHK1 in CML still need to be developed. This study revealed the role of SPHK1 in CML and investigated the potential anti-leukemic activity of hirsuteine (HST), an indole alkaloid obtained from the oriental plant Uncaria rhynchophylla, in CML cells. These results suggest that SPHK1 is highly expressed in CML cells and that overexpression of SPHK1 represents poor clinical outcomes in CML patients. HST exposure led to G2/M phase arrest, cellular apoptosis, and downregulation of Cyclin B1 and CDC2 and cleavage of Caspase 3 and PARP in CML cells. HST shifted sphingolipid rheostat from sphingosine 1-phosphate (S1P) towards the ceramide coupled with a marked inhibition of SPHK1. Mechanistically, HST significantly blocked SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways. In addition, HST can be docked with residues of SPHK1 and shifts the SPHK1 melting curve, indicating the potential protein-ligand interactions between SPHK1 and HST in both CML cells. SPHK1 overexpression impaired apoptosis and proliferation of CML cells induced by HST alone. These results suggest that HST, which may serve as a novel and specific SPHK1 inhibitor, exerts anti-leukemic activity by inhibiting the SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways in CML cells, thus conferring HST as a promising anti-leukemic drug for CML therapy in the future.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.126-137
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• 2006

In the present study, the author intended to investigate whether three oriental medical prescriptions named Jeongcheonhwadam-tang(JHT), Haengso-tang(HST), Socheungryong-tang(SCRT) significantly affect mucin release from cultured hamster tracheal surface epithelial (HTSE) cells. The results were as follows: (1) JHT significantly inhibited mucin release from cultured HTSE cells, without significant cytotoxicity : (2) HST significantly inhibited mucin release from cultured HTSE cells, without significant cytotoxicity : (3) SCRT significantly inhibited mucin release from cultured HTSE cells, without significant cytotoxicity : (4) JHT, HST chiefly inhibited the 'mucin' release and did not significantly affect the release of the other releasable glycoproteins with less molecular weight than mucin. These results suggest that the three herbal prescriptions specifically inhibit the release of mucin: (5) JHT significantly inhibited the expression levels of MUC SAC mRNA. This result suggests that JHT affects the synthesis of mucin at gene level in cultured HTSE cells. All agents showed no significant cytotoxicity. In view of these results, further investigation of the effects of JHT and HST are likely to be instrumental in yielding novel agents from oriental medical prescriptions which have inhibitory effects or expectorative effects on airway mucus secretion.

• Wind and Structures
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• v.34 no.4
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• pp.335-353
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• 2022

The current work numerically investigates the transient force and dynamic response of an overhead transmission tower-line structure caused by the passage of a high-speed train (HST). Taking the CRH2C HST and an overhead transmission tower-line structure as the research objects, both an HST-transmission line fluid numerical model and a transmission tower-line structure finite element model are established and validated through comparison with experimental and theoretical data. The transient force and typical dynamic response of the overhead transmission tower-line structure due to HST-induced wind are analyzed. The results show that when the train passes through the overhead transmission tower-line structure, the extreme force on the transmission line is related to the train speed with a significant quadratic function relationship. Once the relative distance from the track is more than 15 m, the train-induced force is small enough to be ignored. The extreme value of the mid-span dynamic response of the transmission line is related to the train speed and span length with a significant linear functional relationship.

• Journal of Drive and Control
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• v.19 no.1
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• pp.34-42
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• 2022

Hydrostatic transmission (HST) comprises rotary parts, shafts, valve plate, swashplate, and servo pistons. Ensuring structural stability of each part of an HST has a significant impact on product safety. In this study, the structural stability of HST in agricultural machinery and industrial vehicles was analyzed using ANSYS software. For conservative evaluation, high-pressure conditions (35.5 MPa and 2 MPa pilot pressure) were applied as load conditions. The number of grids used in the calculations ranged from 0.4 to 0.8 million depending on modeling requirements. Structural analysis was performed for essential parts and safety factor was analyzed. All major parts of HST had a safety factor of ≥ 1.5. Thus, they were judged to be structurally safe. This study provides important information for designing an HST system.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1519-1521
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• 1998

A Gapless HST(high speed train) arrester design is not possible without the highly non-linear ZnO(ZincOxide) varistors. Zno varistors combine excellent protective characteristics with steady state performance to maximize protection, the ZnO varistors are selected for each unit based on leakage current and residual voltage, to verify that the residual voltage is the residual voltage published for HST arrester.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.3
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• pp.33-38
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• 2002

This paper deals with pressure ripple attenuation far separated-type Hydrostatic Transmission (HST) consisting ova variable axial piston pump connected in an open loop to a fried displacement axial piston motor. Pressure ripples in HST is major source of vibration which can lead to fatigue failure of components and cause noise. In order to reduce the pressure ripple, an annular tube tripe hydraulic filter is proposed to attenuate pressure ripples with the high frequencies components to achieve better noise reduction in HST. The basic principle of a hydraulic filter is allied to propagation of pressure wave, reflection, absorption in cross section of discontinuity and resonance in the hydraulic pipeline. It is experimentally shown that the hydraulic filter attenuates about 30∼40dB of pressure ripple with high frequencies. These results will assist in modeling and design of noise reduction in hydraulic control systems, and provide a means of designing a quieter HST.

• Journal of Drive and Control
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• v.11 no.3
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• pp.41-46
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• 2014

The neutral valve for controlling the HST is one of the important valves for the vehicle control. Neutral valve takes a role of blocking or transmitting power to the vehicle. The operating principle of the neutral valve was developed through the analysis model. We also investigated the logical validity by analyzing the results of the analysis model. The analysis model was developed by using SimulationX witch is commercial software. The number of holes in the piston was selected as a variable initial compression of the spring, and the magnitude of the pressure pulsations and the diameter of the orifice for the sensitivity analysis were performed to design sensitivity analysis of the neutral valve.

• The Journal of Korean Medicine
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• v.29 no.3
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• pp.76-87
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• 2008

Objectives: In this study, the author investigated whether Haengso-tang (HST) and Chwiyeon-tang (CHT) affect both in vitro mucin secretion and MUC5AC gene expression in airway epithelial cells and in vivo mucin secretion from animal model for airway mucus hypersecretion. Materials and Methods: Confluent HTSE cells (non-labeled) were chased for 30 min in the presence of HST and CHT to assess the effects of the agents on mucin secretion by enzyme-linked immunosorbent assay (ELISA), with removal of oriental herbal medicine extract from each agent-treated sample by centrifuge microfilter. Also, the effects of the agents on TNF- or EGF-induced MUC5AC gene expression in human airway epithelial cells (NCI-H292) were investigated. The author also induced hypersecretion of airway mucus by exposure of rats to SO2 for 3 weeks. Effects of orally-administered HST and CHT during 1 week on in vivo mucin secretion from tracheal goblet cells of rats were assessed using ELISA. Results: (1) HST significantly decreased in vitro mucin secretion from cultured HTSE cells. However, CHT did not affect in vitro mucin secretion from HTSE cells; (2) CHT significantly inhibited the expression levels of EGF- or TNF-alpha-induced MUC5AC gene in NCI-H292 cells. However, HST did not affect the expression levels of EGF- or TNF-alpha-induced MUC5AC gene in NCI-H292 cells; (3) CHT significantly inhibited hypersecretion of in vivo mucin. However, HST did not affect hypersecretion of in vivo mucin. Conclusion: These results suggest that CHT can not only affect the secretion of mucin but also the expression of the mucin gene and could be helpful for treating pulmonary disease caused by secretion of mucin.