Identification of molecular target of AMP-activated protein kinase activator by affinity purification and mass spectrometry

We show an efficient method to identify molecular targets of small molecular compounds by affinity purification and mass spectrometry. Binding proteins were isolated from target cell lysate using affinity columns, which immobilized the active and inactive compounds. All proteins bound to these affinity columns were eluted by digestion using trypsin and then were identified by mass spectrometry. The specific binding proteins to the active compound, a candidate for molecular targets, were determined by subtracting the identified proteins in an inactive compound-immobilized affinity column from that in an active compound-immobilized affinity column. This method was applied to identification of molecular targets of D942, a furancarboxylic acid derivative, which increases glucose uptake in L6 myocytes through AMP-activated protein kinase (AMPK) activation. To elucidate the mechanism of AMPK activation by D942, affinity columns that immobilized D942 and its inactive derivative, D768, were prepared, and the binding proteins were purified from L6 cell lysate. NAD(P)H dehydrogenase [quinone] 1 (complex I), which was shown as one of the specific binding proteins to D942 by subtracting the binding proteins to D768, was partially inhibited by D942, not D768. Because inhibition of complex I activity led to a decrease in the ATP/AMP ratio, and the change in the ATP/AMP ratio triggered AMPK activation, we identified complex I as a potential protein target of AMPK activation by D942. This result shows our approach can provide crucial information about the molecular targets of small molecular compounds, especially target proteins not yet identified.     

Flow Behavior in Z-Path Fluidized-Moving Bed with Inclined Perforated Plate

Ｔｈｅｓｔａｃｋｅｄ/ ｐａｃｋｅｄｂｅｄｉｓｇｅｎｅｒａｌｌｙｕｓｅｄｆｏｒｌａｒｇｅｐａｒｔｉｃｌｅｓ .Ｉｎｓｕｃｈａｂｅｄ ,ｇａｓ ｓｏｌｉｄｒｅａｃｔｉｏｎｉｓｒｅｌａｔｉｖｅｌｙｓｌｏｗ ,ａｎｄｐａｒｔｉｃｌｅｓｓｈｏｕｌｄｂｅｏｆｇｏｏｄｍｅ ｃｈａｎｉｃａｌｐｒｏｐｅｒｔｉｅｓ .Ｓｏ ,ｉｔｓａｐｐｌｉｃａｔｉｏｎｉｓｌｉｍｉｔｅｄ .Ｔｈｅｒａｉｎｉｎｇｂｅｄｉｓｏｐｅｒａｔｅｄｗｉｔｈｌｅｓｓｅｎｔｒａｉｎｍｅｎｔｏｆｐａｒｔｉｃｌｅｓ .Ｔｈｅｒｅａｒｅｆｅｗａｐｐｌｉｃａｔｉｏｎｓｉ…     

Analysis of discontinuities in a grounded slab waveguide by combination of finite-element and boundary-element methods

A combined approach of the finite-element and boundary-element methods is formulated for the analysis of arbitrarily shaped discontinuities in a grounded slab waveguide. In this approach, the discontinuity region is divided into two regions. One is a finite region with arbitrary inhomogeneities; the other is a semi-infinite and homogeneous region. The finite-element and the boundary-element methods are applied to the former and the latter regions, respectively, Also, analytical solutions in which both the guided and the radiation modes are taken into account are used for uniform waveguide regions connected to the discontinuity region. To show the validity and usefulness of this approach, computed results are given for several kinds of discontinuities, and some of them are compared with theoretical results previously published. © 1992 John Wiley & Sons, Inc.     

Thermal diffusivity of SiO2 and Y2O3 added AIN ceramics

The addition of both SiO₂ and Y₂O₃ to AIN led to decrease of 27R polytype in specimens sintered above 1600° C and also to an increase of thermal diffusivity of AIN ceramics. Furthermore, SiO₂ and Y₂O₃ added AIN ceramics were fully densified by liquid-phase sintering, and resulted in higher thermal diffusivity. The formation temperature of the liquid phase was lowered more by the addition of both SiO₂ and Y₂O₃ than only Y₂O₃ to AIN ceramics.     

Dynamics of a recurrent neural network acquired through learning a context-based attention task

Selective attention is a very important function for robots acting in the real world. In this function, not only attention itself, but also context extraction and retention are very intelligent processes and are not easily realized. In this article, an attention task is presented in which context information must be extracted from the first pattern presented, and using the context information, a recognition response must be generated from the second pattern presented. An Elman-type recurrent neural network is used to extract and retain the context information. The reinforcement signal that indicates whether the response is correct or not is the only signal given to the system during learning. By this simple learning process, the necessary context information got to be extracted and retained, and then the system changed to generate the correct responses. The function of associative memory was also observed in the feedback-loop in the Elman-type neural network. Furthermore the adaptive formation of basins was examined by varying the learning conditions. This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002.     

Carnitine/organic cation transporter OCTN2-mediated transport of carnitine in primary-cultured epididymal epithelial cells

Carnitine is essential for the acquisition of motility and maturation of spermatozoa in the epididymis, and is accumulated in epididymal fluid. In this study, carnitine transport into primary-cultured rat epididymal epithelial cells was characterized to clarify the nature of the transporter molecules involved. Uptake of carnitine by primary-cultured epididymal epithelial cells was time, Na(+) and concentration dependent. Kinetic analysis of carnitine uptake by the cells revealed the involvement of high- and low-affinity transport systems with Km values of 21 microM and 2.2 mM respectively. The uptake of carnitine by the cells was significantly reduced by inhibitors of carnitine/organic cation transporter (OCTN2), such as carnitine analogues and cationic compounds. In RT-PCR analysis, OCTN2 expression was detected. These results demonstrated that the high-affinity carnitine transporter OCTN2, which is localized at the basolateral membrane of epididymal epithelial cells, mediates carnitine supply into those cells from the systemic circulation as the first step of permeation from blood to spermatozoa.     

Neural filtering method for stationary signal processes

In this paper a new method of neural filtering using artificial neural network systems is presented for the filtering problems of linear and nonlinear, stationary and nonstationary stochastic signals. The neural filter (denoted neurofilter) developed in this paper has either finite impulse response (FIR) structure or infinite impulse response (IIR) structure. The neurofilter differs from the conventional linear digital FIR and IIR filters because the artificial neural network system used in the neurofilter has a nonlinear structure due to the sigmoid function. Numerical studies for the estimation of a second-order Butterworth process are performed by changing the structures of the neurofilter in order to evaluate the performance indices under changes of the output noises or disturbances. The results obtained from these studies verified the capabilities which are essentially necessary for on-line filtering of various stochastic signals.     

Fast pattern recognition using a neurocomputer

This paper presents a new pattern recognition system based on moment invariants using a neurocomputer. The new pattern recognition system consists of a CCD video camera, an image processing system named FDM, a monitor, two stand lights, an NEC PC-9801 microcomputer and a RICOH RN-2000 neurocomputer; these two different types of computers can be considered to constitute an artificial brain. Experimental studies to recognize five dynamic patterns of Japanese chestnuts were performed. From the studies, a high speed of both learning and recognition has been achieved compared with the former pattern recognition system based on the software of artificial neural networks developed by us. This work was presented, in part, at the International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20, 1996     

Three-Dimensional Simulation of the Ventricular Depolarization and Repolarization Processes and Body Surface Potentials: Nornal Heart and Bundle Branch Block

A three-dimensional computer model has been constructed to simulate the ventricular depolarization and repolarization processes in a human heart. The electrocardiogram (ECG), the vectorcardiogram(VCG), and the body surface potential map (BSPM) during the QRS-T period are obtained automatically under certain heart conditions such as bundle branch block and myocardial infarctions. The ventricles, together with bundle branches and the Purkinje fibers, are composed of approximately 50 000 cell units which are arranged in a cubic close-packed structure. A different action potential waveform was assigned to each unit. The heart model is mounted in a homogeneous human torso model. Electric dipoles, which are proportional to the spatial gradient of the action potential, are generated in all the cell units. These dipoles give rise to a potential distribution on the torso surface, which is calculated by means of the boundary element method. The resulting ECG's, VCG's, and BSPM's are within the expected range of clinical observations.