Development of Measurement Equipment of Membrane Stress Using White Noise Sound Wave

Jin, Sang-Wook,Ohmori, Hiroshi,Kim, Jae-Yeol 한국공간구조학회 2008 한국공간구조학회지 Vol.8 No.2

휨이나 압축에 저항할 수 없는 막재료에 적절한 장력을 도입함으로써 안정화 되는 막구조물은, 유지 관리면에 있어서 막면에 도입되어 있는 장력을 설계대로 유지하는 것이 매우 중요하지만, 준공후 막면에 도입되어 있는 장력을 정확하게 파악하기가 어렵다. 저자들은, 직방형의 경계를 가지는 막을 가청역의 음파를 이용해 진동시키고, 진동하는 막의 공진진동수를 측정함으로써 간접적으로 막장력을 측정하는 방법을 제안하고, 막을 진동시키는 음파로서 정현파와 화이트 노이즈를 이용해 검증실험을 해 왔다. 본 논문은 주요 막재료를 이용해 행한 막장력 측정 이론의 검증을 위한 실험 결과와, 실재하는 막구조물의 장력측정을 통해, 본 측정장치의 정확성과 폭 넓은 적용성 및 측정에 있어서의 안정성을 검증한다. One of the most important matters in keeping membrane structures in healthy condition is to maintain the proper tension distribution over the membrane. However, it is not easy to know the real stress level in the membrane quantitatively after completion of the structures. Authors suggested measurement method that can measure membrane stress using sound wave, and have been holding experimental tests of membrane stress measurement that used the sound external excitation with sine wave and white noise. The concept of the method is the fact that measurement of resonance frequency by vibrating membrane having rectangular boundary by audible frequency can measure membrane stress indirectly. In this paper, through the experimental tests it is proved that the equipment can be used for not only the membrane material of type A but also for types B and C. In addition, it is proved that the developed measurement equipment is available to stably measure the membrane stress which exists in the membrane material of the actual membrane structures.

화이트 노이즈 음파를 이용한 막구조물의 장력 측정장치 개발

진상욱,Hiroshi Ohmori,김재열 한국공간구조학회 2008 한국공간구조학회지 Vol.8 No.2

One of the most important matters in keeping membrane structures in healthy condition is to maintain the proper tension distribution over the membrane. However, it is not easy to know the real stress level in the membrane quantitatively after completion of the structures. Authors suggested measurement method that can measure membrane stress using sound wave, and have been holding experimental tests of membrane stress measurement that used the sound external excitation with sine wave and white noise. The concept of the method is the fact that measurement of resonance frequency by vibrating membrane having rectangular boundary by audible frequency can measure membrane stress indirectly. In this paper, through the experimental tests it is proved that the equipment can be used for not only the membrane material of type A but also for types B and C. In addition, it is proved that the developed measurement equipment is available to stably measure the membrane stress which exists in the membrane material of the actual membrane structures.

Reactive Oxygen Species and Nitrogen Species Differentially Regulate Neuronal Excitability in Rat Spinal Substantia Gelatinosa Neurons

Hae In Lee,A-Reum Park,Sang Woo Chun KOREAN ACADAMY OF ORAL BIOLOGY 2014 International Journal of Oral Biology Vol.39 No.4

Reactive oxygen species (ROS) and nitrogen species (RNS) are implicated in cellular signaling processes and as a cause of oxidative stress. Recent studies indicate that ROS and RNS are important signaling molecules involved in nociceptive transmission. Xanthine oxidase (XO) system is a well-known system for superoxide anions (O2 -) generation, and sodium nitroprusside (SNP) is a representative nitric oxide (NO) donor. Patch clamp recording in spinal slices was used to investigate the role of O2- and NO on substantia gelatinosa (SG) neuronal excitability. Application of xanthine and xanthine oxidase (X/XO) compound induced membrane depolarization. Low concentration SNP (10 μM) induced depolarization of the membrane, whereas high concentration SNP (1 mM) evoked membrane hyperpolarization. These responses were significantly decreased by pretreatment with phenyl N-tert-butylnitrone (PBN; nonspecific ROS and RNS scavenger). Addition of thapsigargin to an external calcium free solution for blocking synaptic transmission, led to significantly decreased X/XO-induced responses. Additionally, X/XO and SNP-induced responses were unchanged in the presence of intracellular applied PBN, indicative of the involvement of presynaptic action. Inclusion of GDP-β-S or suramin (G protein inhibitors) in the patch pipette decreased SNP-induced responses, whereas it failed to decrease X/XO-induced responses. Pretreatment with n-ethylmaleimide (NEM; thiol-alkylating agent) decreased the effects of SNP, suggesting that these responses were mediated by direct oxidation of channel protein, whereas X/XO-induced responses were unchanged. These data suggested that ROS and RNS play distinct roles in the regulation of the membrane excitability of SG neurons related to the pain transmission.

Fluorescence spectrum-based biofouling prediction method for RO membrane systems

Hwang, Sun-Nyoung,Choi, Wooyeol,Lim, Hyuk,Choi, Jinhee,Kim, Hyunjung,Chang, In Seop Balaban Publishers 2012 Desalination and Water Treatment Vol.43 No.1

<P> Monitoring reverse osmosis (RO) membrane conditions is an important task because it helps reduce the operation and maintenance cost in the RO membrane desalination systems by achieving long membrane lifetime and energy saving. As biological interactions between the membrane itself and microorganism cause the rapid degradation of membrane performance, it is crucial to identify and quantify potential biofoulants that are sensitive to each specific RO membrane. This study proposed a biofouling prediction method that indirectly quantifies the degree of biofouling by comparing the fluorescence excitation-emission matrix (EEM) of foulants sampled on the fully fouled RO membrane and those of brine samples from currently operating RO system. The experiment showed that the similarity distance measured from the comparison between the two fluorescence EEMs tends to increase when brine samples were secured from relatively clean RO membranes. </P>

Dynamic Stability of Liquid in a Spherical Tank Covered with Membrane under Vertical Harmonic Excitation

Chiba, Masakatsu,Murase, Ryo,Nambu, Yohsuke,Komatsu, Keiji The Society for Aerospace System Engineering 2015 International Journal of Aerospace System Engineer Vol.2 No.2

Experimental studies were conducted on the liquid sloshing characteristics in a spherical tank covered with a flexible membrane. A spherical acrylic tank with 145.2 mm in radius was used as a test tank, and it was half-filled with water. Silicon membranes with 0.2 mm thickness were used as a test membrane with plane or hemispherical types. The test tank was harmonically excited in a vertical direction by an electro-dynamic exciter. In this case, a parametric instability vibration comes up when the excitation frequency is twice the natural frequency. Parametric instability regions of natural modes were measured for three cases, i.e. liquid surface is free, covered with plane membrane and hemi-spherical membrane.

β-Adrenergic signaling is required for the induction of a labile state during memory reconsolidation

Lim, Chae-Seok,Kim, Jae-Ick,Kwak, Chuljung,Lee, Jaehyun,Jang, Eun Hae,Oh, Jihae,Kaang, Bong-Kiun Elsevier 2018 Brain research bulletin Vol.141 No.-

<P><B>Abstract</B></P> <P>Memory reconsolidation is the process by which previously consolidated memories reenter a labile state through reactivation of the memory trace and are actively consolidated through <I>de novo</I> protein synthesis. Although extensive studies have shown that β-adrenergic signaling plays a critical role in the restabilization of reactivated memory, its role in the destabilization of long-term memory is not well-studied. In this study, we found that membrane excitability increased in hippocampal CA1 neurons immediately after the retrieval of contextual fear memory. Interestingly, this increase in membrane excitability diminished after treatment with propranolol (a β-adrenergic receptor antagonist), an NMDA receptor antagonist, and a PKA inhibitor. In addition, we found that administration of propranolol prior to, but not after, the retrieval of fear memory ameliorated the memory impairment caused by anisomycin, indicating that inhibition of β-adrenergic signaling blocks the destabilization of contextual fear memory. Taken together, these results indicate that β-adrenergic signaling via NMDA receptors and PKA signaling pathway induces a labile state of long-term memory through increased neuronal membrane excitability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Retrieval of contextual fear memory increases the membrane excitability. </LI> <LI> Propranolol or NMDAR and PKA inhibition diminishes membrane hyperexcitability. </LI> <LI> β-adrenergic signaling is required for the destabilization of contextual fear memory. </LI> </UL> </P>

Action of Mitochondrial Substrates on Neuronal Excitability in Rat Substantia Gelatinosa Neurons

이해인,천상우 대한구강생물학회 2017 International Journal of Oral Biology Vol.42 No.2

Recent studies indicate that mitochondria are an important source of reactive oxygen species (ROS) in the spinal dorsal horn. In our previous study, application of malate, a mitochondrial electron transport complex I substrate, induced a membrane depolarization, which was inhibited by pretreatment with ROS scavengers. In the present study, we used patch clamp recording in the substantia geletinosa (SG) neurons of spinal slices, to investigate the cellular mechanism of mitochondrial ROS on neuronal excitability. DNQX (an AMPA receptor antagonist) and AP5 (an NMDA receptor antagonist) decreased the malate-induced depolarization. In an external calcium free solution and addition of tetrodotoxin (TTX) for blockade of synaptic transmission, the malateinduced depolarization remained unchanged. In the presence of DNQX, AP5 and AP3 (a groupⅠ metabotropic glutamate receptor (mGluR) antagonist), glutamate depolarized the membrane potential, which was suppressed by PBN. However, oligomycin (a mitochondrial ATP synthase inhibitor) or PPADS (a P2 receptor inhibitor) did not affect the substrates-induced depolarization. These results suggest that mitochondrial substrate-induced ROS in SG neuron directly acts on the postsynaptic neuron, therefore increasing the ion influx via glutamate receptors.

Active Vibration Control of a Membrane Structure Using PVDF Actuator

Yuelin Zhang,Toshiki Hiruta,Itsuro Kajiwara,Naoki Hosoya 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.춘계 No.-

To realize a vibration suppression of flexible structures like a membrane, the smart structures technology that uses material such as piezoelectric element is focused. In this study, a vibration control system using a PVDF film as an actuator for the membrane structure is proposed. To confirm the effectiveness of the proposed method, the control properties with H<SUB>∞</SUB> control for reducing single mode, 1st or 2nd mode vibration, are evaluated by using the non-contact laser excitation vibration test system. In the system, a high power pulse laser is used for producing an ideal impulse excitation and a laser Doppler vibrometer is used for measuring the response on the membrane. The obtained results show that the vibration suppression is achieved at each mode in all experiments. Therefore, the present method using the flexible piezoelectric element is effective to suppress the vibration of flexible structures.

Bifurcation and chaos of the traveling membrane on oblique supports subjected to external excitation

Mingyue Shao,Jiajuan Qing,Jimei Wu 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

This paper analyzes bifurcation and chaos of the traveling membrane on oblique supports subjected to external excitation. Through coordinate transformation, the Von Karman nonlinear plate theory was employed to derive the non-linear governing equations of membrane on oblique supports in terms of axial movement in the oblique coordinate system. The boundary conditions were also given in the oblique coordinate system. The approximate solution for the governing equations was found via the Galerkin method as well as the fourthorder Runge-Kutta numerical computing method. The nonlinear dynamic techniques including Lyapunov exponents diagrams, bifurcation plots, Poincare maps, phase trajectories, and time histories were introduced to analyze the impacts of the angles of oblique supports, aspect ratios and traveling velocities on dynamics responses and the various forms of vibration regarding the membrane system.

Effects of Hesperidin Are Not Associated with Changes in Basal Synaptic Transmission, Theta-burst LTP, and Membrane Excitability in CA1 Neuron

Jinhee Baek,김재익,강봉균 한국통합생물학회 2009 Animal cells and systems Vol.13 No.4

Hesperidin, the most abundant polyphenolic compound found in citrus fruits, has been known to possess neuroprotective, sedative, and anticonvulsive effects on the nervous system. In a recent electrophysiological study, it was reported that hesperidin induced biphasic change in population spike amplitude in hippocampal CA1 neurons in response to both single spike stimuli and theta-burst stimulation depending on its concentration. However, the precise mechanism by which hesperidin acts on neuronal functions has not been fully elucidated. Here, using wholecell patch-clamp recording, we revealed that hesperidin did not affect excitatory synaptic activities such as basal synaptic transmission and theta-burst LTP. Moreover, in a current injection experiment, spike number, resting membrane potential and action potential threshold also remained unchanged. Taken together, these results indicate that the effects of hesperidin on the neuronal functions such as spiking activity might not be attributable to either modification of excitatory synaptic transmissions or changes in membrane excitability in hippocampal CA1 neuron. Hesperidin, the most abundant polyphenolic compound found in citrus fruits, has been known to possess neuroprotective, sedative, and anticonvulsive effects on the nervous system. In a recent electrophysiological study, it was reported that hesperidin induced biphasic change in population spike amplitude in hippocampal CA1 neurons in response to both single spike stimuli and theta-burst stimulation depending on its concentration. However, the precise mechanism by which hesperidin acts on neuronal functions has not been fully elucidated. Here, using wholecell patch-clamp recording, we revealed that hesperidin did not affect excitatory synaptic activities such as basal synaptic transmission and theta-burst LTP. Moreover, in a current injection experiment, spike number, resting membrane potential and action potential threshold also remained unchanged. Taken together, these results indicate that the effects of hesperidin on the neuronal functions such as spiking activity might not be attributable to either modification of excitatory synaptic transmissions or changes in membrane excitability in hippocampal CA1 neuron.