• Journal of Microbiology and Biotechnology
• /
• 제21권10호
• /
• pp.1088-1096
• /
• 2011

The purpose of this study was to evaluate whether wild ginseng (WG) administration could attenuate anxiety- and depression-like behaviors and expression of corticotrophin-releasing factor (CRF) and neuropeptide Y (NPY) following withdrawal from repeated morphine administration in rats. Male rats were administered daily doses of WG (50, 100, or 200 mg/kg, i.p.) for 5 days, 30 min before morphine injection (40 mg/kg, s.c). The anxiety- and depression-like behavioral responses were measured 72 h after the last morphine injection using an elevated plus maze (EPM) and forced swimming test (FST), respectively. Changes in hypothalamic CRF and NPY expressions were also examined by analyzing their immunoreactivities in the hypothalamus. Daily administration of WG significantly reduced anxiety- and depression-like behavior, and elicited the suppression of CRF expression and the stimulation of NPY expression in the hypothalamus. Our results demonstrated that WG extract might be effective at inhibiting the anxiety and depression responses due to morphine withdrawal by possibly modulating the hypothalamus CRF and NPY systems. Furthermore, these findings imply that WG extract can be used for developing new medication to cure or alleviate morphine withdrawal symptoms and to prevent relapses of morphine use.

• Journal of Power Electronics
• /
• 제19권5호
• /
• pp.1224-1234
• /
• 2019

Hybrid rotor position estimation methods that integrate a fundamental model and high frequency (HF) signal injection are widely used for the wide speed-range sensorless control of interior permanent-magnet synchronous machines (IPMSMs). However, the direct transition of two different schemes may lead to system fluctuations or system instability since two estimated rotor positions based on two different schemes are always unequal due to the effects of parameter variations, system delays and inverter nonlinearities. In order to avoid these problems, a seamless transition strategy to define and construct a virtual q-axis inductance is proposed in this paper. With the proposed seamless transition strategy, an estimated rotor position based on a fundamental model is forced to track that based on HF signal injection before the transition by adjusting the constructed virtual q-axis inductance. Meanwhile, considering that the virtual q-axis inductance changes with rotor position estimation errors, a new observer with a two-phase phase-locked loop (TP-PLL) is developed to accurately obtain the virtual q-axis inductance online. Furthermore, IPMSM sensorless control with maximum torque per ampere (MTPA) operations can be tracked automatically by selecting the proper virtual q-axis inductance. Finally, experimental results obtained from an IPMSM demonstrate the feasibility of the proposed seamless transition strategy.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.1482-1487
• /
• 2004

In general the swirl jet is generated by the injected flow that is forced to the tangential direction. A spiral nozzle which is composed of an annular slit and a convergent nozzle, is released the spiral jet that is generated by the radial flow injection through an annular slit. The objective of the present study is to investigate the additional study that is studied a changed the convergent nozzle angle and nozzle length. In the present computation, a finite volume scheme is used to solve three dimensional Navier-Stokes equations with RNG $k-{\varepsilon}$ turbulent model. The convergent nozzle angle and the nozzle length of the spiral nozzle are varied to obtain different spiral flows inside the conical convergent nozzle. The present computational results are compared with the previous experimental data. The results obtained show that the convergent nozzle angle and the nozzle length of the spiral jet strongly influence the characteristics of the spiral jets, such as a tangential and a jet width.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.502-507
• /
• 2003

Spiral jet is characterized by a wide region of the free vortex flow with a steep axial velocity gradient, while swirl jet is largely governed by the forced vortex flow and has a very low axial velocity at the jet axis. However, detailed generation mechanism of spiral flow components is not well understood, although the spiral jet is extensively applied in a variety of industrial field. In general, it is known that spiral jet is generated by the radial flow injection through an annular slit which is installed at the inlet of convergent nozzle. The objective of the present study is to understand the flow characteristics of the spiral jet, using a computational method. A finite volume scheme is used to solve 3-dimensional Navier-Stokes equations with RNG ${\kappa}-{\varepsilon}$ turbulent model. The computational results are validated by the previous experimental data. It is found that the spiral jet is generated by coanda effect at the inlet of the convergent nozzle and its fundamental features are dependent the pressure ratio of the radial flow through the annular slit and the coanda wall curvature.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.2029-2034
• /
• 2004

Spiral jet is characterized by a wide region of the free vortex flow with a steep axial velocity gradient, while swirl jet is largely governed by the forced vortex flow and has a very low axial velocity at the jet axis. However, detailed generation mechanism of spiral flow components is not well understood, although the spiral jet is extensively applied in a variety of industrial field. In general, it is known that spiral jet is generated by the radial flow injection through an annular slit which is installed at the inlet of a conical convergent nozzle. The present study describes a computational work to investigate the effects of annular slit on the spiral jet. In the present computation, a finite volume scheme is used to solve three dimensional Naver-Stokes equations with RNG ${\kappa}-{\varepsilon}$ turbulent model. The annular slit width and the pressure ratio of the spiral jet are varied to obtain different spiral flows inside the conical convergent nozzle. The present computational results are compared with the previous experimental data. The results obtained obviously show that the annular slit width and the pressure ratio of the spiral jet strongly influence the characteristics of the spiral jets, such as tangential and axial velocities.

• 한국공작기계학회논문집
• /
• 제14권4호
• /
• pp.32-40
• /
• 2005

The purpose of this study is to investigate variation of spark plug protrusion and PDA valve on the exhaust emission in a gasoline engine. Swirl is one of the important parameters that affects the characteristics of combustion. PDA valve has been developed to satisfy requirements of sufficient swirl generation for improving the combustion and reducing of emission level. Also, especially, the variation of spark plug protrusion have an important effect to the early flame propagative process. This is largely due to the high flame speed by short of flame propagation distance. So, this is forced that injection timing, spark timing and intake air motion govern the stable combustion. As a result, using two combustion chamber, without charge of engine specification and the variable spark plug location and PDA valve could be reduced exhaust gas at a part load engine conditions(1500rpm imep 3.9bar, 2000rpm imep 3.2bar, 2400rpm imep 3.9bar).

• 항공우주기술
• /
• 제10권2호
• /
• pp.65-73
• /
• 2011

위성의 발사 후 정지궤도위성을 운용궤도에 진입시키기 위해서는 전이궤도 원지점 (Apogee)에서 위성에 장착된 액체원지점엔진을 발사하여 근지점(Perigee) 고도를 정지궤도 고도에 이르도록 높여준다. 이 과정에서 궤도결정 결과를 피드백하여 정밀하게 궤도조정을 수행하고 종료 후 원하는 경도에 안착시키기 위해 상황에 따라 엔진발사를 3회에서 4회로 나누어 수행하게 된다. 본 논문에서는 먼저 임펄스 형태의 기동을 가정하여 각 액체원지점 엔진 발사시점과 ${\Delta}V$ 벡터를 결정하기 위한 알고리즘을 수립하였고, 추가적으로 연속점화에 따른 오차를 보정하기 위한 기법을 제안하였다. 또한 시뮬레이션을 통하여 제안된 기법의 타당성을 분석하였다.

• 대한약침학회지
• /
• 제20권4호
• /
• pp.257-264
• /
• 2017

Introduction: Pharmacopuncture, which combines acupuncture with herbal medicine, is one of the newly developed acupuncture techniques that has recently been put into use. The possible mechanisms of scolopendra pharmacopuncture, as well as its potential effects on depressive symptoms, were investigated in this study by using a mouse model of chronic immobilization stress (CIS). Methods: C57BL/6 male mice were randomly assigned into three groups: mice not stressed with restraint and injected with distilled water, mice stressed with restraint and injected with distilled water, and mice stressed with restraint injected with scolopendra pharmacopuncture at a cervical site. Behavioral tests (an open field test, tail suspension test, and forced swimming test) were carried out after two weeks of CIS and injection treatments. The expression levels of glial fibrillary acidic protein (GFAP) in the hippocampus were determined by using western blot and immunohistochemistry analyses. Results: Mice exposed to CIS showed decreased behavioral activity, while scolopendra pharmacopuncture treatment significantly protected against the depressive-like behaviors induced by CIS. Moreover, scolopendra pharmacopuncture treatment increased GFAP protein levels in the hippocampi of the mice stressed by chronic immobilization. Conclusion: Scolopendra pharmacopuncture has an ameliorating effect on depressive behavior, which is partially mediated through protection against glial loss in the hippocampus.

• The Korean Journal of Physiology and Pharmacology
• /
• 제16권6호
• /
• pp.379-386
• /
• 2012

The purpose of this study was to evaluate whether berberine (BER) administration could attenuate depression- and anxiety-like behaviors and increase corticotrophin-releasing factor (CRF) and tyrosine hydroxylase (TH) expression following chronic morphine withdrawal in rats. Male rats were exposed to chronic, intermittent, escalating morphine (10~50 mg/kg) for 10 days. After the last morphine injection, depression- and anxiety-like beahvior associated with morphine discontinuation persisted for at least three days during withdrawal without any change in ambulatory activity. Daily BER administration significantly decreased immobility in the forced swimming test and increased open-arm exploration in the elevated plus maze test. BER administration also significantly blocked the increase in hypothalamic CRF expression and TH expression in the locus coeruleus (LC) and the decrease in hippocampal brain-derived neurotrophic factor (BDNF) mRNA expression. Taken together, these findings demonstrated that BER administration significantly reduced morphine withdrawal-associated behaviors following discontinuation of repeated morphine administration in rats, possibly through modulation of hypothalamic CRF and the central noradrenergic system. BER may be a useful agent for treating or alleviating complex withdrawal symptoms and preventing morphine use relapses.

• 사상체질의학회지
• /
• 제27권2호
• /
• pp.270-287
• /
• 2015

Objectives To evaluate the neuroprotective effects of modified Yuldahanso-tang (MYH) in a Parkinson's disease mouse model. Methods 1) Four groups (each of 8 rats per group) were used in this study. 2) The neuroprotective effect of MYH was examined in a Parkinson's disease mouse model. C57BL/6 mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day), intraperitoneal (i.p.) for 5 days. 3) The brains of 2 mice per group were removed and frozen at $-20^{\circ}C$, and the striatum-substantia nigra part was seperated. The protein volume was measured by Bradford method following Bio-Rad protein analyzing kit. Using mouse/Rat Dopamine ELISA Assay Kit. 4) The brains of 2 mice per group were separated and removed. TH-immunohistochemical was examined in the MPTP-induced Parkinson's disease mice to evaluate the neuroprotective effects of MYH on ST and SNpc. 5) Two mice out of each group were anesthetized and skulls were opened from occipital to frontal direction to take out the brains. The brains added TTC solution for 20 minutes for staining. 6) The water tank used for morris water maze test was filled with $28^{\circ}C$ water, and a round platform of 10cm in diameter was installed for mice to step on. The study was carried out once a day within 30 seconds, keep exercising to step on the platform in the pool. 7) The brains of two mice out of each group were fixed in 10% formaldehyde solution and paraphillin substance was infiltrated. They were fragmented by microtome, and observed under an optical microscope after Hematoxylin & Eosin staining. 8) A round acrylic cylinder with its upper side open was filled with clean water and depressive mouse models were forced to swim for 15 minutes. After 24 hours the animals were put in the same equipment for 5 minutes and were forced to swim. 9) The convenient, simple, and accurate high-performance liquid chromatography (HPLC) method was established for simultaneous determination of Neurotransmitters in MPTP-MYH group. Results 1) MYH possess Dopamine cell protective effect on MPTP-induced injury in striatum and substantia nigra pars compacta. 2) MYH inhibits the loss of tyrosine hydroxylase-immunoreacitive (TH-IR) cells in the striatum and substantia nigra pars compacta on MPTP-induced injury in C57BL/6 mice. 3) MYH possesses improvement effect on MPTP-induced memory deterioration in C57BL/6 mice through the reduction of prolongated Sort of lost time by MPTP injection using the Morris water maze test. 4) MYH possesses hippocampal neuron protective effect on MPTP-induced injury in C57BL/6 mice. 5) MYH possesses improvement effect on MPTP-induced motor behaviour deficits and depression in C57BL/6 mice through the reduction of prolongated losing motion by MPTP injection using the Forced swimming test. 6) MYH increases serotonin product amount on MPTP-induced injury in C57BL/6 mice. Conclusions This experiment suggests that the neuroprotective effect of MYH is mediated by the increase in Dopamin, TH-ir cell, Hippocampus and Serotonin. Furthermore, MYH essential oil may serve as a potential preventive or therapeutic agent regarding Parkinson's disease.