Unique Crystal Structure of Ca_{2}RuO_{4} in the Current Stabilized Semimetallic State.

The electric-current stabilized semimetallic state in the quasi-two-dimensional Mott insulator Ca_{2}RuO_{4} exhibits an exceptionally strong diamagnetism. Through a comprehensive study using neutron and x-ray diffraction, we show that this nonequilibrium phase assumes a crystal structure distinct from those of equilibrium metallic phases realized in the ruthenates by chemical doping, high pressure, and epitaxial strain, which in turn leads to a distinct electronic band structure. Dynamical mean field theory calculations based on the crystallographically refined atomic coordinates and realistic Coulomb repulsion parameters indicate a semimetallic state with partially gapped Fermi surface. Our neutron diffraction data show that the nonequilibrium behavior is homogeneous, with antiferromagnetic long-range order completely suppressed. These results provide a new basis for theoretical work on the origin of the unusual nonequilibrium diamagnetism in Ca_{2}RuO_{4}.

A study on white organic light-emitting diodes co-doped with red fluorescent and blue phosphorescent dopants.

White organic light-emitting diodes (WOLEDs) have drawn increasing attention due to their potential use in various applications such as solid-state lighting and backlight of liquid crystal displays and full-color OLEDs of red, green, and blue pixel. N,N'-dicabazolyl-3,5-benzene (mCP), the host material, was co-doped with Iridium (III) bis[(4,6-difluorophenyl)-pyridinato-N,C2']-picolinate (FIrpic), which functions not only as phosphorescent sensitizer but also blue emitter, and (2Z,2'Z)-3,3'-[4,4"-bis (dimethylamino)-1,1':4',1"-terphenyl-2',5'-diyl]bis (2-phenylacrylonitrile) (ABCV-P), which is a red fluorescent material. The fabricated device structures were as follows: (device A) Indium tin oxide (ITO)/N,N'-bis-(1-naphyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB)/(mCP)/mCP:ABCV-P (1%)/4,7-diphenyl-1,10-phenanthroline (Bphen)/lithium quinolate (Liq)/aluminum (Al), (device B) ITO/NPB/mCP/mCP:FIrpic (8%)/Bphen/Liq/Al and (device C) ITO/NPB/mCP/mCP:FIrpic:ABCV-P (8%, 1%)/Bphen/Liq/Al, respectively. Phosphorescent FIrpic harvesting both singlet and triplet excitions not only emitted blue light but also transferred energy to fluorescent ABCV-P. The maximum luminance efficiency, external quantum efficiency, and luminance of white light device were measured to be 5.95 cd/A, 2.45% and 2500 cd/m2, respectively. The white device gave practically white light with the Commision Internationale de l'Eclairage (CIE(xy)) coordinate of (0.44, 0.49) which was close to warm white color (CIE(xy) = 0.45, 0.45).

A non-doped organic light emitting diode with pure red emission using a new host emitter.

A red fluorescent material (2E,2'E)-3,3'-[4,4"-bis(dimethylamino)-1,1': 4',1 "-terphenyl-2',5'-diyl]bis[2-(2-thienyl)acrylonitrile] (ABCV-Th) was synthesized for use in organic light emitting diodes (OLEDs) as the host emissive material. It has been reported some green and blue host emissive materials used in OLEDs revealed high device performance but, owing to concentration quenching, comparable red light emitting materials are still rare in OLEDs application. Non-doped organic light emitting diodes, with the structure of ITO/NPB/ABCV-Th (30 nm and 50 nm)/BCP/Alq3/Liq/Al were fabricated using ABCV-Th as the host emitter. The peak wavelength and full width at half maximum (FWHM) of electroluminescence (EL) were 629.5 nm and 68.5 nm, respectively. The maximum brightness and turn on voltage of the device were measured to be 1330 cd/m2 at 14.6 V and 3.4 V, respectively. The device exhibited authentic red emission (Commission Internationale De L'Eclairage (CIE(xy)) = 0.65, 0.34) which is almost close to the standard red (CIE(xy) = 0.67, 0.33) demanded by the national television system committee (NTSC).

The Effects of Temperature on the Hydrothermal Synthesis of Hydroxyapatite-Zeolite Using Blast Furnace Slag.

Blast furnace slag, an industrial by-product, is emerging as a potential raw material to synthesize hydroxyapatite and zeolite. In this study, the effects of temperature on the hydrothermal synthesis of hydroxyapatite-zeolite from blast furnace slag were investigated. Specimens were synthesized at different temperatures (room temperature, 50, 90, 120, or 150 °C). The synthesized specimens were analyzed qualitatively and quantitatively via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), BET/BJH, and scanning electron microscopy/energy dispersive using X-ray analysis (SEM/EDX). It was found that the hydroxyapatite phase was synthesized at all the reaction temperatures, while faujasite type zeolite appeared in the specimens synthesized at 90 and 120 °C. Moreover, faujasite was replaced by hydroxysodalite in the specimens synthesized at 150 °C. Additionally, the crystals of the hydroxyapatite tended to become larger and total crystallinity increased as the reaction temperature increased.

Dependence of surface morphology on molecular structure and its influence on the properties of OLEDs.

Most organic light-emitting diodes (OLEDs) have a multilayer structure composed of organic layers such as a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (EIL) sandwiched between two electrodes. The organic layers are thin solid films with a thickness from a few nano meters to a few tenths nano meter, respectively. Surface morphology of an organic thin solid film in OLEDs depends on the molecular structure of the organic material and has an affect on device performance. To analyze the effect of surface morphology of an organic thin solid film on fluorescence and electroluminescence (EL) properties, thin solid films of 4-(dicyanomethylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran (DCM2) and new red fluorophores, (2E,2'E)-3,3'-[4,4''-bis(dimethylamino)-1,1':4',1''-terphenyl-2',5'-diyl]bis[2-(2-thienyl)acrylonitrile] (ABCV-Th) and (2Z,2'Z)-3,3'-[4,4''-bis(dimethylamino)-1,1':4',1''-terphenyl-2',5'-diyl]bis(2-phenylacrylonitrile) (ABCV-P) were investigated by atomic force microscopy (AFM). The samples for EL and AFM measurement were fabricated by the high-vacuum thermal deposition (8 x 10(-7) Torr) of organic materials onto the surface of indium tin oxide (ITO)-coated glass substrate, in which the layer structures of samples for AFM measurement and those for EL measurement were ITO/NPB (40 nm)/red emitters (80 nm) and ITO/NPB (40 nm)/red emitters (80 nm)/BCP (30 nm)/Liq (2 nm)/Al (100 nm), respectively. The analysis based on AFM measurements well supported that the photoluminescence properties and the device performance were very much dependent upon surface morphology of an organic thin layer.

Activator-specific requirement of yeast mediator proteins for RNA polymerase II transcriptional activation.

The multisubunit Mediator complex of Saccharomyces cerevisiae is required for most RNA polymerase II (Pol II) transcription. The Mediator complex is composed of two subcomplexes, the Rgr1 and Srb4 subcomplexes, which appear to function in the reception of activator signals and the subsequent modulation of Pol II activity, respectively. In order to determine the precise composition of the Mediator complex and to explore the specific role of each Mediator protein, our goal was to identify all of the Mediator components. To this end, we cloned three previously unidentified Mediator subunits, Med9/Cse2, Med10/Nut2, and Med11, and isolated mutant forms of each of them to analyze their transcriptional defects. Differential display and Northern analyses of mRNAs from wild-type and Mediator mutant cells demonstrated an activator-specific requirement for each Mediator subunit. Med9/Cse2 and Med10/Nut2 were required, respectively, for Bas1/Bas2- and Gcn4-mediated transcription of amino acid biosynthetic genes. Gal11 was required for Gal4- and Rap1-mediated transcriptional activation. Med11 was also required specifically for MFalpha1 transcription. On the other hand, Med6 was required for all of these transcriptional activation processes. These results suggest that distinct Mediator proteins in the Rgr1 subcomplex are required for activator-specific transcriptional activation and that the activation signals mediated by these Mediator proteins converge on Med6 (or the Srb4 subcomplex) to modulate Pol II activity.

Exendin-4 induction of cyclin D1 expression in INS-1 beta-cells: involvement of cAMP-responsive element.

Glucagon-like peptide-1 (GLP-1) and its analog exendin-4 (EX) have been considered as a growth factor implicated in pancreatic islet mass increase and beta-cell proliferation. This study aimed to investigate the effect of EX on cyclin D1 expression, a key regulator of the cell cycle, in the pancreatic beta-cell line INS-1. We demonstrated that EX significantly increased cyclin D1 mRNA and subsequently its protein levels. Although EX induced phosphorylation of Raf-1 and extracellular-signal-regulated kinase (ERK), both PD98059 and exogenous ERK1 had no effect on the cyclin D1 induction by EX. Instead, the cAMP-elevating agent forskolin induced cyclin D1 expression remarkably and this response was inhibited by pretreatment with H-89, a protein kinase A (PKA) inhibitor. Promoter analyses revealed that the cAMP-responsive element (CRE) site (at position -48; 5'-TAACGTCA-3') of cyclin D1 gene was required for both basal and EX-induced activation of the cyclin D1 promoter, which was confirmed by site-directed mutagenesis study. For EX to activate the cyclin D1 promoter effectively, CRE-binding protein (CREB) should be phosphorylated and bound to the putative CRE site, according to the results of electrophoretic mobility shift and chromatin immunoprecipitation assays. Lastly, a transfection assay employing constitutively active or dominant-negative CREB expression plasmids clearly demonstrated that CREB was largely involved in both basal and EX-induced cyclin D1 promoter activities. Taken together, EX-induced cyclin D1 expression is largely dependent on the cAMP/PKA signaling pathway, and EX increases the level of phosphorylated CREB and more potently trans-activates cyclin D1 gene through binding of the CREB to the putative CRE site, implicating a potential mechanism underlying beta-cell proliferation by EX.

Direct association of Bloom's syndrome gene product with the human mismatch repair protein MLH1.

Bloom's syndrome (BS) is a rare genetic disorder characterised by genomic instability and cancer susceptibility. BLM, the gene mutated in BS, encodes a member of the RecQ family of DNA helicases. Here, we identify hMLH1, which is involved in mismatch repair (MMR) and recombination, as a protein that directly interacts with BLM both in vivo and in vitro, and that the two proteins co-localise to discrete nuclear foci. The interaction between BLM and hMLH1 appears to have been evolutionarily conserved, as Sgs1p, the Saccharomyces cerevisiae homologue of BLM, interacts with yeast Mlh1p. However, cell extracts derived from BS patients show no obvious defects in MMR compared to wild-type- and BLM-complemented BS cell extracts. We conclude that the hMLH1-BLM interaction is not essential for post-replicative MMR, but, more likely, is required for some aspect of genetic recombination.

The endonuclease activity of the yeast Dna2 enzyme is essential in vivo.

Dna2 is a multifunctional enzyme in yeast that possesses endonuclease activity well suited to remove RNA-DNA primers of Okazaki fragments, raising the question of whether endonuclease activity is essential for in vivo Dna2 function. Systematic site-directed mutations of amino acid residues in Saccharomyces cerevisiae DNA2 conserved in the central region of many eukaryotic DNA2 homologs allowed us to identify mutant dna2 alleles that were divided into three groups based on the viability of the mutant cells: (i) viable; (ii) inviable only when expression was repressed; (iii) inviable. Biochemical analyses of recombinant mutant Dna2 proteins isolated from the latter two groups revealed that they possessed normal ATPase/helicase activity, but were impaired in their endonuclease activity. Cells expressing mutant Dna2 enzymes partially impaired in endonuclease activity were viable, but were unable to grow when expression of their mutant Dna2 enzymes was further reduced. Their growth was restored when the mutant Dna2 proteins decreased in nuclease activity were induced to overexpress. In contrast, mutant Dna2 proteins lacking endonuclease activity did not allow cells to grow under any conditions tested. These in vivo and in vitro results demonstrate that the endonuclease activity of Dna2 is essential for Okazaki fragment processing.

Structure and superconductivity of (Li1-x Fe x )OHFeSe single crystals grown using A x Fe2-y Se2 (A = K, Rb, and Cs) as precursors.

We present results on the hydrothermal growth of ([Formula: see text])OHFeSe single crystals using floating-zone-grown [Formula: see text] (A = K, Rb, and Cs) as precursors. The growth proceeds by the hydrothermal ion exchange of Li/Fe-O-H for K, Rb, and Cs, resulting in a stacking layer of ([Formula: see text])OH sandwiched between the FeSe layers. Optimal growth parameters are achieved using high quality A 0.80Fe1.81Se2 single crystals added to the mixtures of LiOH, H2O, Fe and C(NH2)2Se in an autoclave and subsequently heated to 120 °C for 2 d, to obtain highest quality single crystals. The obtained crystals have lateral dimensions up to centimeters, with the final size related to that of the precursor crystal used. All ([Formula: see text])OHFeSe single crystals show a superconducting transition temperature T c > 42 K, regardless of the phase of the precursor such as superconducting K0.80Fe1.81Se2 (T c = 29.31 K) or non-superconducting Rb0.80Fe1.81Se2 or poor-superconducting Cs0.80Fe1.81Se2 (T c = 28.67 K). The T c and transition width ΔT vary in the obtained single crystals, due to the inhomogeneity of the ionic exchange. X-ray diffraction analysis demonstrates that the 245 insulating phase is absent in the ion-exchanged single crystals, while it is observed in the [Formula: see text] precursors. Comparative studies of the structure, magnetization, and superconductivity on the parent A 0.80Fe1.81Se2 and the ion-exchanged ([Formula: see text])OHFeSe crystals are discussed. A phase diagram including antiferromagnetic spin density wave and superconducting phases is also proposed.

Severe anaphylactic reaction after primary exposure to aprotinin.

Aprotinin is widely used to prevent bleeding and reduce blood transfusions after open heart surgical procedures. Because it is a foreign protein, aprotinin has allergenic potential. We report a case of near-fatal anaphylactic reaction to primary aprotinin exposure in a child successfully treated using cardiopulmonary bypass support. The possibility of an allergic reaction must be considered whenever this drug is used.

Six-week trial of nebulized flunisolide nasal spray: efficacy in young children with moderately severe asthma.

This study evaluated the clinical efficacy of nebulized flunisolide nasal solution (Nasalide) in young children with moderately severe asthma. Twenty-two asthmatic children, ages 12-72 months, completed this double-blind placebo-controlled study. After a 6-week observation period, 18 patients were paired according to asthma severity. One child from each pair was randomized to flunisolide, the other to placebo; 4 patients were independently randomized. Placebo or drug was then administered for 6 weeks. Throughout the study, symptoms, drug usage, and analog scales reflecting asthma severity and family disruption were recorded in a diary. Multiple regression analysis was used to compare the flunisolide and placebo groups in regard to the amount of improvement demonstrated from the observation to the active periods of the study. Analog scores of asthma severity and family disruption, albuterol aerosol use, and systemic corticosteroid use fell roughly 40% from baseline in the flunisolide group. This improvement was significant compared to the placebo group. We conclude that 1 ml (250 microg) of nebulized flunisolide nasal spray solution, administered three times daily, reduced the severity of asthma symptoms, and the need for both albuterol aerosol and systemic corticosteroid therapy in young children with moderately severe asthma during a 6-week trial. Longer term studies are warranted.

A moving-actuator type electromechanical total artificial heart--Part II: Circular type and animal experiment.

A new type of electromechanical total artificial heart (TAH) based on circular rolling-cylinder mechanism was developed to overcome critical problems in motor-driven artificial hearts such as large size and difficulties in fitting the heart to atrial remnants and arterial vessels. Its performance and reliability were evaluated in mock circulation and in an animal implant experiment. The total weight and volume of the pump is 650 g and 600 mL, respectively. This new pump was implanted in a calf for total heart replacement and 96 h of survival was achieved. The whole system, including pump, controller, and control algorithm performed well enough to improve the prospect of eventual clinical application of our TAH system.

Cardioprotective drugs decrease the Na+ background current.

Cardiac dysfunctions such as myocardial functional failure and ventricular arrhythmia have been largely attributed to intracellular Ca2+ overload. One of the mechanisms of intracellular Ca2+ overload involves a rapid influx of Ca2+ via Na(+)-Ca2+ exchange during the reperfusion which utilizes the accumulation of Na+ in myocytes during ischemic cardiac arrest. Possible sources of the intracellular Na+ accumulation include Na+ channel, Na(+)-H+ exchange, Na(+)-Ca2+ exchange, and Na+ background current. In this study, we studied the role of the Na+ background current in intracellular Na+ accumulation during the cardiac arrest by measuring the Na+ background current in guinea pig ventricular myocytes with whole cell clamp method and evaluating the effects of cardioprotective drugs on the Na+ background current. The results were as follows: (1) The Na+ background inward current at -40 mV membrane potential was larger at Ca2+ free solution than 1.8 mM Ca2+ solution. (2) The Na+ background current was not affected by verapamil. (3) 2 microM O-(N, N-hexamethylene)-amiloride (HMA) decreased the Na+ background current at negative membrane potential. (4) The new cardioprotective drug, R 56865, decreased the Na+ background current. These results suggest that the Na+ background current plays a role in increasing the intracellular Na+ activity during high K+ cardioplegia and the blocking effect of myoprotective drugs, such as R 56865, on the Na+ background current may contribute to myocardial protection after cardioplegia.

Albumin immobilized polyurethane and its blood compatibility.

Surface pretreatment with albumin on a blood contacting material inhibits platelet adhesion, activation, and subsequent thrombus formation. Although adsorbed albumin improves blood compatibility, rapid desorption occurs when this surface is exposed to circulating blood. In this study, human serum albumin was immobilized on a polyurethane (PU) surface to investigate its blood compatibility and extended effects on a blood-material interface. The PU surface was treated with hexamethylene diisocyanate (HMDI), and the PU-HMDI was further grafted with albumin to produce an albumin immobilized PU surface (PU-albumin). The PU-albumin surface was characterized by attenuated total reflection infrared electron spectroscopy for chemical analysis, scanning electron microscopy, and dynamic contact angle. Blood compatibility was evaluated by in vitro protein adsorption, platelet adhesion, and occlusion time in an ex vivo rabbit arterio-arterial shunt. Immobilization of albumin was confirmed by the disappearance of the -NCO peak observed at 2,250 cm-1 on the PU-HMDI surface by infrared spectroscopy and the existence of sulfur atomic percent by electron spectroscopy for chemical analysis. The concentration of PU-albumin was approximately 5.8 micrograms/cm2. The PU-albumin also showed a slight increase in hydrophilicity on the Wilhelmy plate method, and there was less fibrinogen adsorption than a PU control. In addition, PU-albumin had less platelet adhesion, platelet activation, and thrombogenicity. The ex vivo occlusion time of untreated PU was 50 min, that of PU-albumin was extended to 150 min, indicating that a PU-albumin surface has better blood compatibility than PU alone.

Antithrombotic activity of a lumbrokinase immobilized polyurethane surface.

Six fractions of strong and novel fibrinolytic enzymes (lumbrokinase, LK) were extracted from the earthworm Lumbricus rubellus. The enzymes in these fractions appeared to be very stable and showed greater antithrombotic activity than other currently used antithrombotics. The authors immobilized an LK fraction that shows the most potent fibrinolytic activity on a polyurethane (PU) surface to investigate its enzymatic and antithrombotic activity. The methanol extracted PU surface was treated with a 3% (wt/vol) maleic anhydride methylvinyl ether copolymer (MAMEC) solution and finally incubated in an LK solution in PBS (pH 7.4). The immobilized LK activity was estimated by the fibrin plate method and caseinolytic activity assay. The antithrombotic activity was evaluated by in vitro 125I-fibrinogen adsorption in fresh whole blood and 99mTc platelet adhesion tests. In addition, the occlusion time was determined through ex vivo rabbit A-A shunt experiments. The content and unit activity of immobilized LK were found to be 24 micrograms/cm2 and 18 IU/cm2, respectively. The relative activity ratio of immobilized LK to soluble LK was found to be approximately 34%. Immobilized LK was stable within a various pH range and resistant to inhibitors and thermal inactivation. Less fibrinogen was adsorbed and fewer platelets adhered on an LK-immobilized surface than on PU and PU-MAMEC controls. The ex vivo occlusion time of untreated PU and PU-MAMEC surfaces were only 32 and 42 minutes, respectively. But that of LK-immobilized PU was extended to 140 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of shear rates on protein adsorption in the total artificial heart.

Plasma protein adsorption is the first event in blood-material interaction and influences subsequent platelet adhesion and thrombus formation. Thromboembolic events are strongly influenced by surface characteristics of materials and fluid dynamics inside the blood pump. In vitro flow visualization, and an animal experiment with a moving actuator total artificial heart (TAH), were performed to investigate fluid dynamic effects on protein adsorption. The different levels of shear rate inside the ventricle were determined by considering the direction of opening of the four heart valves in the implanted TAH, and the visualized flow patterns as well. Each ventricle of the explanted TAH was cut into 12 segments according to the shear rate level. The adsorbed protein on each segment was quantified using an ELISA method after soaking in 2% (w/v) SDS/PBS for 2 days. Adsorbed protein layer thicknesses were measured by the immunogold method under transmission electron microscopy. Scanning electron microscopic observation showed that the right ventricle, immobilized with albumin, displayed different degrees of platelet adhesion on each segment, whereas the left ventricle, coated with polythyleneoxide-sulfonate, indicated nearly the same platelet adhesion behavior, regardless of shear rates. The surface concentrations of adsorbed proteins in the low shear rate region are higher than those in the high shear region, which was confirmed statistically.

The fluid dynamic effect on protein adsorption in left ventricular assist devices.

Plasma protein adsorption onto an artificial surface is strongly influenced by not only the surface characteristics of materials, but also by the fluid dynamics inside the blood pump, and it would influence subsequent platelet adhesion or activation, which plays a major role in the initiation of thrombus formation at the blood-material interface in vivo. In vitro flow visualization of an electrohydraulic LVAD was performed by a video camera (CCD, Hitachi) and an image processor (PC VISION PLUS) with an IBM PC. The electrohydraulic LVADs were implanted in mongrel dogs of approximately 20 kg. The authors sectioned the blood contacted ventricle after animal death according to the level of shear rate. Because analysis of adsorbed protein might be influenced by the size of the ventricle segment, the number of segments was limited to eight per ventricle. Platelet adhesion and its morphology were observed by scanning electron microscopy (SEM). Adsorbed plasma proteins (fibrinogen, albumin, and IgG) on each segment were quantified by enzyme linked immunosorbent assay (ELISA). The specimens were soaked in 2% (wt/vol) SDS/PBS for 2 days and the released protein concentration assessed. A well developed large vortex was observed at the center of the artificial ventricle. Polyurethane blood pumps displayed different degrees of protein adsorption and subsequent platelet adhesion on each segment.

Effect of shear stress on fibrinogen adsorption and its conformational change.

The composition and molecular organization of adsorbed protein films are strongly correlated with thrombogenesis on artificial surfaces. In particular, the antibody-detectable (that is, conformationally intact) bound fibrinogen, but not that the total amount of adsorbed fibrinogen, is correlated with platelet reactivity. In this work, the authors quantified the adsorbed plasma protein distribution inside the left ventricular assist device. They also evaluated the effect of wall shear stress on protein adsorption and conformational change of adsorbed fibrinogen. Conformational change of adsorbed fibrinogen was measured by exposing the fibrinogen preadsorbed polyurethane to three anti-fibrinogen monoclonal antibodies; the 134B-29 detectable alpha 566-580 domain of fibrinogen was increased with increasing concentration of adsorbed fibrinogen, whereas the other two fibrinogen domains were almost saturated when increasing the concentration of adsorbed fibrinogen. The adsorbed amounts of total fibrinogen and monoclonal antibody detectable fibrinogen was decreased with increasing shear rate. Results of in vivo plasma protein adsorption on polyurethane surfaces disclosed that the adsorbed amount of fibrinogen, as well as albumin and globulin, was also decreased with increasing shear rate. In conclusion, less protein was adsorbed in the higher shear region and the effect of shear level on fibrinogen adsorption and its conformational change was strongly dependent upon the surface characteristics of the biomaterials. The monoclonal antibody 134B-29 against the 566-580 domain of fibrinogen was the most reactive with the fibrinogen adsorbed on polyurethane surfaces in this experiment.

A new antioxidant monoterpene glycoside, alpha-benzoyloxypaeoniflorin from Paeonia suffruticosa.

Alpha-benzoyloxypaeoniflorin (1), a new antioxidant monoterpene alpha-glycoside anomer was isolated from Paeonia suffruticosa along with known compounds, beta-benzoyloxypaeoniflorin (2), paeonolide, paeoniflorin and mudanpioside H. The structure of 1 has been determined by comparing spectral data with those of beta-benzoyloxypaeoniflorin (2). Compound 1 exhibited moderately potent radical scavenging activity on DPPH radical.