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Local environment surrounding Zr atoms in the thin films of nanocrystalline zirconia (ZrO2) has been investigated by using the extended x-ray absorption fine structure (EXAFS) technique. These films prepared by the ion beam assisted deposition exhibit long-range structural order of cubic phase and high hardness at room temperature without chemical stabilizers. The local structure around Zr probed by EXAFS indicates a cubic Zr sublattice with O atoms located on the nearest tetragonal sites with respect to the Zr central atoms, as well as highly disordered locations. Similar Zr local structure was also found in a ZrO2 nanocrystal sample prepared by a sol-gel method. Variations in local structures due to thermal annealing were observed and analyzed. Most importantly, our x-ray results provide direct experimental evidence for the existence of oxygen vacancies arising from local disorder and distortion of the oxygen sublattice in nanocrystalline ZrO2. These oxygen vacancies are regarded as the essential stabilizing factor for the nanostructurally stabilized cubic zirconia. [ABSTRACT FROM AUTHOR]

We have investigated the effects of local structures on the orientational motions in liquid water in terms of the instantaneous normal mode (INM) analysis. The local structures of a molecule in liquid water are characterized by two different kinds of index: the asphericity parameter of its Voronoi polyhedron and the numbers of the H bonds donated and accepted by the molecule. According to the two kinds of index, the molecules in the simulated water are classified into subensembles, for which the rotational contributions to the INM spectrum are calculated. Our results indicate that by increasing the asphericity, the rotational contribution has a shift toward the high-frequency end in the real spectrum and a decrease in the fraction of the imaginary modes. Furthermore, we find that this shift essentially relies on the number of the donated H bonds of a molecule, but has almost nothing to do with that of the accepted H bonds. The local structural effects resulting from the geometry of water molecule are also discussed. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The continuous inversion from a water-in-oil (w/o) microemulsion at low temperatures to an oil-in-water (o/w) microemulsion at higher temperatures within the one-phase channel of water (0.6% NaCl)–n-decane–AOT microemulsion system is investigated by small angle neutron scattering (SANS). At constant AOT (surfactant) weight fraction γ of 12%, the structural evolution as a function of temperature takes place in different forms as the oil-to-water weight fraction α is varied from 15 to 90 %. At low o-w weight fractions (α=15 and 20 %) the microemulsions transform from a water-internal, oil-continuous structure at lower temperatures to an oil-internal, water-continuous droplet structure at higher temperatures jumping across an intermediate region of a lamellar phase (Lα). However, at higher o-w weight fractions (α=80 and 90 %) the evolution goes through a stage of percolation of the water droplets first into extended water clusters, then the structural inversion takes place probably through a transition of these water clusters into an entangled tubular structure. At equal oil-to-water volume ration (α=40%), the structure can be described as bicontinuous at both low and high temperatures. In this case we are able to extract two lengths characterizing the structure from SANS data using different models for the scattering length density fluctuation correlation function of a bicontinuous microemulsion. [ABSTRACT FROM AUTHOR]

We have investigated the temperature and coverage-dependent transformations of the ordered structures of oxygen on Pd(100). The four ordered structures are the chemisorbed c(2×2) and p(2×2) lattices, and the reconstructed p(5×5) and ((5)1/2×(5)1/2)R27° lattices. We present evidence that the p(5×5) reconstruction forms in an activated stepfrom c(2×2) regions. The onset of p(5×5) formation is associated with an increase in oxygen sticking coefficient. In thermal desorption, there are three states which can be correlated directly with the structure of the adsorbed phase during desorption: At lowest coverage, the α state shows the traits of second-order kinetics and is due to desorption from a disordered adlayer. At higher coverage, the β state appears and is due to desorption from a layer with c(2×2) order. There is a lower barrier to desorption in the β state than in the α state because of the repulsive second-nearest-neighbor interactions in the c(2×2). At highest coverage, the sharp and narrow γ state emerges. This is accompanied by decomposition of the ((5)1/2×(5)1/2)R27° reconstruction, in which cooperative stabilization of the reconstruction by oxygen atoms effectively creates strong quasiattractive oxygen–oxygen interactions. There are interesting similarities between the oxygen-stabilized reconstructions of Pd(100) and the initial stages of oxidation of Ni(100), as well as the oxygen-stabilized reconstructions of Pt(100). The data are obtained from low-energy electron diffraction coupled with a computer-interfaced Video camera, Auger electron spectroscopy, and thermal desorption spectroscopy. [ABSTRACT FROM AUTHOR]

This study aimed to study the effect of different color combinations of LED light on the quantity of primordia, the formation of the fruiting body, and the yield of bioactive ingredients produced in solid culture C. militaris. The results show that appropriate color combinations and light intensities of Light-Emitting Diodes (LEDs) can significantly increase the quantity of primordia, promote the formation of fruiting bodies, and increase the yield of bioactive ingredients (cordycepin, adenosine, mannitol, and polysaccharides) in solid culture of Cordyceps militaris. LEDs have several advantages such as small size, long lifespan, fast response time, high efficiency and stability, and the ability to emit a narrow wavelength range of monochromatic light from a cold source. Our results show that both red and green-LEDs can shorten the period of primordia appearance. Red-LED increased the number of primordia and biological efficiency and red and blue LED combinations increased the biomass of the fruiting body. A light intensity of 1,000 Lux resulted in the fastest appearance of primordia, and the highest average fruiting body biomass and biological efficiency. Under different red and blue LED combinations, the highest amounts of cordycepin, adenosine, mannitol, and polysaccharide in the fruiting body of C. militaris were 15.63±0.72 (100 Lux), 23.17±1.22 (1,000 Lux), 19.84±0.84 (300 Lux), and 28.69±1.52 mg g-1 (1,000 Lux), respectively. Appropriate color combinations and intensities of LED light can significantly increase the quantity of the primordium, promote the formation of the fruiting body, and increase the yield of bioactive ingredients produced in solid culture C. militaris. [ABSTRACT FROM AUTHOR]

We describe a two-parameter continuation algorithm for computing Bloch waves of Bose-Einstein condensates (BEC) in optical lattices which is governed by the Gross-Pitaevskii equation (GPE). The Fourier collocation method and fourthorder Adini's elements with penalty are used to discretize the GPE. We propose two different approaches so that the two-parameter continuation algorithm can be modified to compute closed tubes at the four corners of the Bloch band. We also study linear stability analysis for the GPE. We show that all the discrete steady-state solutions are numerically neutrally stable. Numerical results show that the four edges of the Bloch waves are surrounded by closed loops if the coefficient of the cubic nonlinear term is greater than that of the periodic potential. Moreover, closed tubes at the four corners of the Bloch band are obtained. The numerical results display superfluidity of BEC. [ABSTRACT FROM AUTHOR]

Detailed considerations of how to construct inclined-incidence hard X-ray resonators are presented. Owing to the symmetry of the crystals used, the Bragg back reflection usually employed in normal-incidence two- and multi-plate resonators to reflect the X-ray beam is often accompanied by unavoidable multiple-beam diffraction, and thus the reflectivity and cavity finesse are quite low. In contrast, crystal-based Fabry-Perot (FP) resonators at inclined incidence utilize multiple-beam diffraction to excite the back reflection inside the resonator to generate FP resonance with high efficiency, while avoiding the incident beam suffering from crystal absorption. The useful characteristics of inclined-incidence resonators are derived from numerical calculations based on the inclined-incidence diffraction geometry and the dynamical theory. Experimental results with Laue inclined incidence are in accordance with the simulation. The sub-millielectronvolt energy resolution and ultra-high efficiency of the transmission spectrum of the proposed resonators are also described. [ABSTRACT FROM AUTHOR]

Having to sit oral tests is tense particularly for individuals who have poor command of the language being tested. This study examines students' reasons in perceiving an oral test as the easiest or hardest and analyses whether they perform poorly (achieving the lowest score) in the test which they perceived as being the most difficult by comparing their perceived oral test difficulty and perceived oral test performance with their actual oral test performance. The study examined 63 students, selected by means of purposive sampling. Data of the survey research were obtained through a self-administered questionnaire and from students' test scores. The descriptive analysis revealed that the prepared individual speech was perceived as the easiest test, followed by the impromptu two-way communication, 20-minute group discussion and the 30-minute group discussion, while the most difficult test was the impromptu individual speech. Besides that, the top four challenges faced by students in the oral tests which they perceived as being the most difficult were insufficient ideas and/or elaboration, time constraint, being nervous and lack of preparation. The implications of the research on adequacy of oral practice were also discussed as the findings provided better understanding of the challenges faced by participants in oral tests. [ABSTRACT FROM AUTHOR]

We demonstrate the effective self-assembly of Au nanoparticles array by porous anodic alumina templates. It is interesting that 'triangular island' nanostructure appears on the surface of porous anodic alumina template. Every 'triangular island' arises in the adjacent area among three close holes. Using vacuum deposition and thermal dewetting, Au nanoparticles ordered hexagonal array is fabricated on the porous anodic alumina. During optical characterisation, the absorption peaks of Au nanoparticles array are red shifted as the incidence angle increases. Also, Raman scattering spectra intensity of Au nanoparticles hexagonal array nanostructure is a hundred times larger than the contrast substrate material. [ABSTRACT FROM AUTHOR]

A modified algorithm for X-ray dynamical diffraction theory is presented for curved boundary crystals and a detailed description of the numerical procedure is given. The simulated and experimental results both show an anomalous focusing behavior in a curved multi-plate crystal cavity of silicon under the back-diffraction condition at a photon energy of 14.4388 keV. The focusing effects are analyzed, within the framework of the dynamical theory of X-ray diffraction, from the excitation of the dispersion surface and modification of the index of refraction with respect to the non-plane-parallel boundaries of a curved crystal cavity. [ABSTRACT FROM AUTHOR]

Establishment and characterization of two cobia, Rachycentron canadum, cell lines derived from cobia brain (CB) and cobia fin (CF) are described. Caudal fin and brain from juvenile cobia were dissociated for 30 and 10 min, respectively, in phosphate-buffered saline containing 0.25% trypsin at 25 °C. The optimal culture condition for both dissociated cells (primary cell culture) was at 28 °C in Leibovitz-15 medium containing 10% foetal bovine serum. The cells have been sub-cultured at a ratio of 1:2 for more than 160 passages over a period of 3 years. Origin of the cultured cells was verified by comparison of their sequences of mitochondrial cytochrome oxidase subunit I genes ( cox I) with the cox 1 sequence from cobia muscle tissue. The cell lines showed polyploidy. No mycoplasma contamination was detected. Susceptibility to grouper iridovirus was observed for the CB cell line but not the CF cell line. Both cell lines expressed green fluorescent protein after being transfected with green fluorescent reporter gene driven by the cytomegalovirus promoter. [ABSTRACT FROM AUTHOR]

In this article, the design parameters of a cutting tool for manufacturing a rotary knife with multi-cutting angles have been studied. An objective function and constraints are defined, and optimized solutions are found by using two methods: global search and sequential quadratic programming. Hobbing and the concept of tooth undercutting were used to manufacture a rotary knife with multi-cutting angles. The proposed method not only improved the manufacturing efficiency over the traditional method (milling and grinding), but also significantly improved the strength of the rotary knife and the chip discharge ability, as shown by the finite-element analysis of the stress distribution and deformation of two different kinds of rotary knives. [ABSTRACT FROM AUTHOR]

We study the bifurcation scenario of nonlinear Schrödinger equations (NLS). The Liapunov-Schmidt reduction is applied to show that the simple bifurcations of a single NLS are pitchfork. The pitchfork bifurcation can be subcritical or supercritical, depending on the coefficient of the cubic term we choose. We also describe numerical methods so that the Liapunov-Schmidt reduction can effectively handle a corank-2 bifurcation point. Next, we apply numerical continuation methods to trace solution curves and surfaces of the NLS, where the system is discretized by the centered difference approximations. Numerical results on two- and three-dimensional M-coupled NLS are reported, where the physical properties such as the effect of trapping potentials, isotropic and nonisotropic trapping potentials, mass conservation constraints, and strong and weak repulsive interactions are considered in our numerical experiments. [ABSTRACT FROM AUTHOR]

We discuss numerical methods for studying numerical solutions of N-coupled nonlinear Schrödin-ger equations (NCNLS), N = 2, 3. First, we discretize the equations by centered difference approximations. The chemical potentials and the coupling coefficient are treated as continuation parameters. We show how the predictor–corrector continuation method can be exploited to trace solution curves and surfaces of the NCNLS, where the preconditioned Lanczos method with iterative refinement is used as the linear solver. When the chemical potential is large enough, we obtain peak solutions of the NCNLS for certain values of the coupling coefficient. The contours of the peak solutions resemble those of the experimental results of Anglin and Ketterle [2002], and Anderson et al. [1995]. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation is commonly associated with dilated pulmonary veins. Stretch has been shown to have mechano-electrical effects. Objective: To investigate whether stretch can increase the arrhythmogenic activity of the pulmonary veins. Methods: The transmembrane action potentials were recorded from rabbit pulmonary veins before and after stretch (100 and 300 mg). Gadolinium and streptomycin (stretch-activated ion channel blockers) were each perfused into the pulmonary veins under a 300-mg stretch. Results: Stretch (0, 100 and 300 mg) force dependently increased the incidence of spontaneous activity (22%, 48% and 83%; p<0.05), mean (standard deviation (SD)) firing rates of spontaneous activity (1.7(0.2), 2.1(0.3) and 3 (0.2) Hz; p<0.05) and incidence of early post-depolarisations (9%, 26% and 61%; p<0.05) and delayed post-depolarisations (0%, 4% and 30%; p<0.05) in 23 pulmonary veins. In the seven preparations with spontaneous activity after the 300-mg stretch, gadolinium (1, 3 and 10 µmol/l) decreased the incidence of spontaneous activity by 43%, 29% and 14%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1) Hz to 0.8 (0.4), 0.3 (0.1) and 0.1(0.1) Hz, respectively (p<0.05). Streptomycin (10 and 40 µmol/l) decreased the incidence of spontaneous activity by 71% and 29%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1) Hz to 1.6 (0.4) and 0.5 (0.3) Hz, respectively (p<0.05). Conclusion: Stretch is an important factor in the electrical activity of the pulmonary vein. Stretch-induced arrhythmogenic activity of the pulmonary vein may contribute to the genesis of atrial fibrillation. [ABSTRACT FROM AUTHOR]

An X-ray Fabry-Perot resonator has been proposed and investigated for more than three decades. The difficulty in realizing such a resonator is mainly due to the strict requirement on coherence for cavity resonance, which is governed by the energy resolution of the incident X-ray photons and the size of the resonator. With the aid of modern micro-and nanotechnology for silicon, such as X-ray lithography, miniature resonators, approximately a few micrometers or smaller, can be prepared. Together with X-ray photons of ultrahigh-energy resolution from synchrotron sources, the required conditions on coherence for cavity resonance are fulfilled. Several X-ray cavities prepared by this means are used in X-ray back-diffraction experiments, where back diffraction acts as mirror reflection for X rays. Resonance interference fringes are observed unambiguously. Attempts to use multilayered materials for cavity fabrication are discussed in relation to X-ray synchrotron experiment. Possible future applications of this X-ray resonator are also mentioned. [ABSTRACT FROM AUTHOR]

No abstract available. [ABSTRACT FROM AUTHOR]

We describe a special Gauss–Newton method for tracing solution manifolds with singularities of multiparameter systems. First we choose one of the parameters as the continuation parameter, and fix the others. Then we trace one-dimensional solution curves by using continuation methods. Singularities such as folds, simple and multiple bifurcations on each solution curve can be easily detected. Next, we choose an interval for the second continuation parameter, and trace one-dimensional solution curves for certain values in this interval. This constitutes a two-dimensional solution surface. The procedure can be generalized to trace a k-dimensional solution manifold. Numerical results in 1D, 2D and 3D second-order semilinear elliptic eigenvalue problems given by Lions [1982] are reported. [ABSTRACT FROM AUTHOR]

We study multigrid methods in the context of continuation methods for reaction–diffusion systems, where the Bi-CGSTAB and GMRES methods are used as the relaxation scheme for the V-cycle, W-cycle and full approximation schemes, respectively. In particular, we apply the results of Brown and Walker [1997] to investigate how the GMRES method can be used to solve nearly singular systems that occur in continuation problems. We show that for the sake of switching branches safely, one would rather solve a perturbed problem near bifurcation points. We propose several multigrid-continuation algorithms for curve-tracking in nonlinear elliptic eigenvalue problems. Our numerical results show that the algorithms proposed have the advantage of being robust and easy to implement. [ABSTRACT FROM AUTHOR]

A validated Computational Fluid Dynamics (CFD) code ICRKFLO was developed for simulations of three-dimensional three-phase reacting flows in Fluid Catalytic Cracking (FCC) riser reactors. It calculates the product yields based on local flow properties by solving the fundamental conservation principles of mass, momentum, and energy for the flow properties associated with the gas, liquid, and solid phases. Unique phenomenological models and numerical techniques were developed specifically for the FCC flow simulation. The models include a spray vaporization model, a particle-solid interaction model, and an interfacial heat transfer model. The numerical techniques include a time-integral approach to overcome numerical stiffness problems in chemical kinetics rate calculations and a hybrid hydrodynamic-kinetic treatment to facilitate detailed kinetics calculations of cracking reactions. ICRKFLO has been validated with extensive test data from two pilot and one commercial FCC units. It is proven to be useful for advanced development of FCC riser reactors. [ABSTRACT FROM AUTHOR]

We study the Lanczos method for solving symmetric linear systems with multiple right-hand sides. First, we propose a numerical method of implementing the Lanczos method, which can provide all approximations to the solution vectors of the remaining linear systems. We also seek possible application of this algorithm for solving the linear systems that occur in continuation problems. Sample numerical results are reported. Copyright © 2002 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We study numerical methods for solving nonlinear elliptic eigenvalue problems which contain folds and bifurcation points. First we present some convergence theory for the MINRES, a variant of the Lanczos method. A multigrid-Lanczos method is then proposed for tracking solution branches of associated discrete problems and detecting singular points along solution branches. The proposed algorithm has the advantage of being robust and can be easily implemented. It can be regarded as a generalization and an improvement of the continuation-Lanczos algorithm. Our numerical results show the efficiency of this algorithm. [ABSTRACT FROM AUTHOR]

The nonlinear Wiener stochastic gradient adaptive algorithm for third-order Volterra system identification application with Gaussian input signals is presented. The complete self-orthogonalisation procedure is based on the delay-line structure of the nonlinear discrete Wiener model. The approach diagonalises the autocorrelation matrix of an adaptive filter input vector which dramatically reduces the eigenvalue spread and results in more rapid convergence speed. The relationship between the autocorrelation matrix and cross-correlation matrix of filter input vectors of both nonlinear Wiener and Volterra models is derived. The algorithm has a computational complexity of O(M[SUP3]) multiplications per sample input where M represents the length of memory for the system model, which is comparable to the existing algorithms. It is also worth noting that the proposed algorithm provides a general solution for the Volterra system identification application. Computer simulations are included to verify the theory. [ABSTRACT FROM AUTHOR]

Taiwan’s indigenous tribes, especially the east coast tribes are not only closely related to Oceania but also with the Australian aborigines. The Ivatans of the Batan Islands in the Philippines are closely related to the Yami tribe of Taiwan as cultural and anthropological studies have shown. Many DRB1 alleles (*15021, *16021, *0404, *04051, *11011, *12021, *1401, *08032) have high allele frequencies (>20%) in certain tribes, suggesting Taiwan’s indigenous tribes are homogeneous populations. These high frequency DRB1 alleles and also some HLA-A-B-DR haplotypes found in Taiwan’s indigenous tribes are also found in Oceania, Australian aborigines, south and north east Asians and American Indians, lending further support to our previous findings that Taiwan’s indigenous tribes are more or less genetically related to both northern and southern Asians, possibly as well as Amerindians. HLA-A*2402 with a remarkably high frequency among Taiwan’s indigenous tribes (52.1%∼86.3%), especially the central mountain tribes, possibly represents not only founder effects and population bottlenecks, but also positive selection of the allele. Although the Ami tribe has the highest ever reported frequencies of the DRB1*0404 and DRB1*0405, these alleles have not been found to be associated with rheumatoid arthritis as previously described for Caucasians. In addition, DRB1*1401 has a high frequency in most tribes but is not associated with psoriasis as previously indicated in some studies, suggesting the involvement of some additional genetic and/or environmental factors mechanism in the development of these diseases. [ABSTRACT FROM AUTHOR]

The Minnan and Hakka people groups, the so-called “Taiwanese”, are the descendants of early settlers from the southeast coast of China during the last few centuries. Genetically they showed affinities to southern Asian populations, as determined by phylogenetic trees and correspondence analysis calculated from HLA allele frequencies. This corresponds historically with the fact that they are the descendants of the southeast coastal indigenous population (Yueh) of China and should therefore not be considered as descendants of “pure” northern Han Chinese. A33-B58-DRB1*03 (A33-Cw10-B58-DRB1*03-DQB1*02), the most common HLA haplotype among “Taiwanese”, with a haplotype frequency of 6.3%, has also been found to be the most common haplotype among Thai-Chinese and Singapore Chinese, two other populations also originating from the southeast coast of China. These observations suggests that this haplotype is the most well-conserved ancient haplotype of the Yueh. [ABSTRACT FROM AUTHOR]

This study investigates corrosion inhibition of steel using thiourea and cations such as aluminium, calcium and magnesium under cathodic control in a 3.5% NaCl solution and in seawater. Steel protection in a 3.5% NaCl solution is normally incomplete under a cathodic potential less electronegative than −1.100 V. However, the protection can be enhanced by nearly 50% by adding either 50 ppm aluminium ion or 75 ppm thiourea in solution, and by almost 90% by the combined use of these additions. This study also analyzes how combining inhibitors and cathodic control may be used to protect steel. Moreover, this investigation monitors pH in the solution, measures zero-resistance current between the graphite-steel couple, as well as analyses cathode reaction products. A mechanism is also proposed to interpret the combined effects of inhibitors and cathodic control on the protection of steel. [ABSTRACT FROM AUTHOR]

In this study, structural changes within the lamina propria and detrusor layers were analysed during development as a function of bladder filling. Second-, third- and full-term foetal bovine bladders were filled to 0%, 25%, 50%, 75% and 100% of their total capacity and snap frozen. The bladders were analysed histochemically and the relative thicknesses of the lamina propria and detrusor were measured. In all gestational stages examined, the total thickness of the bladder wall decreased during bladder filling. The lamina propria of the full-term bladder thinned at a consistently faster rate than did the detrusor. The lamina propria of second and third trimester bladders followed the same thinning pattern, except when the bladders were filled from 25% to 50% of their capacities. At these gestational stages, the detrusor thinned at a faster rate than the lamina propria. Our results demonstrate that the detrusor layer carries tension only during a specific portion of the filling cycle and only during the second and third trimesters. We conclude that the lamina propria acts as the capacitance layer, while the detrusor functions as the “limiting” or “girding” layer to prevent over-distension of the bladder wall. [ABSTRACT FROM AUTHOR]

A new simple formula for calculating the adiabatic flame temperature of fuel/air mixtures has been developed. The formula is usable in a wide range of both fuel and reaction variables. Among the fuels considered for the formula are members of the paraffin, aromatic, olefin and alcohol families, and hydrogen and acetylene. The formula is functionally expressed in terms of the fuel/air ratio, the reaction pressure, the initial mixture temperature and the number of carbon atoms in the individual fuel. By using the formula, the adiabatic flame temperature for a designated fuel and reaction condition can be found within an accuracy of one percent. [ABSTRACT FROM PUBLISHER]

Acupuncture at the Zhongwan acupoint has been widely used in traditional Chinese medicine to relieve symptoms of diabetes mellitus. Our study investigated the effect on plasma glucose of electroacupuncture applied at the Zhongwan acupoint in rat diabetic models. Plasma concentrations of insulin, glucagon and β-endorphin were also determined using radioimmunoassay. A decrease in plasma glucose was observed in rats after electroacupuncture (15 Hz, 10 mA) for 30 min at the Zhongwan acupoint. This was observed in normal rats and rat models with Type II (non-insulin-dependent) diabetes mellitus. No significant effect on plasma glucose was observed in rat models with Type I (insulin-dependent) diabetes mellitus; neither the streptozotocin (STZ)-induced diabetic rats nor the genetic (BB/W) rats. Further, the hypoglycaemic action of electroacupuncture stimulation disappeared in rats with insulin-resistance induced by an injection of human long-acting insulin repeated daily to cause the loss of tolbutamide-induced hypoglycaemia. An insulin-related action can thus be hypothesised. This hypothesis is supported by an increase in plasma insulin-like immunoreactivity after electroacupuncture stimulation in normal rats. Participation of glucagon was ruled out because there was no change in plasma glucagon-like immunoreactivity resulting from electroacupuncture stimulation. In addition to an increase in plasma β-endorphin-like immunoreactivity, the plasma glucose lowering action of electroacupuncture stimulation at Zhongwan acupoint was abolished by naloxone in a sufficient dose to block opioid receptors. Thus we suggest that electroacupuncture stimulation at the Zhongwan acupoint induces secretion of endogenous β-endorphin which reduces plasma glucose concentration in an insulin-dependent manner. [Diabetologia (1999) 42: 250–255] [ABSTRACT FROM AUTHOR]