Quantum Impurity in Luttinger Liquid: Universal Conductance with Entanglement Renormalization

We study numerically the universal conductance of Luttinger liquids wire with a single impurity via the Muti-scale Entanglement Renormalization Ansatz (MERA). The scale invariant MERA provides an efficient way to extract scaling operators and scaling dimensions for both the bulk and the boundary conformal field theories. By utilizing the key relationship between the conductance tensor and ground-state correlation function, the universal conductance can be evaluated within the framework of the boundary MERA. We construct the boundary MERA to compute the correlation functions and scaling dimensions for the Kane-Fisher fixed points by modeling the single impurity as a junction (weak link) of two interacting wires. We show that the universal behavior of the junction can be easily identified within the MERA and argue that the boundary MERA framework has tremendous potential to classify the fixed points in general multi-wire junctions.Comment: 14 pages, 18 figure

DLC2 modulates angiogenic responses in vascular endothelial cells by regulating cell attachment and migration.

Deleted in liver cancer 1 (DLC1) is a RhoGTPase activation protein-containing tumor suppressor that associates with various types of cancer. Although DLC2 shares a similar domain structure with that of DLC1, the function of DLC2 is not well characterized. Here, we describe the expression and ablation of DLC2 in mice using a reporter-knockout approach. DLC2 is expressed in several tissues and in endothelial cells (ECs) of blood vessels. Although ECs and blood vessels show no histological abnormalities and mice appear overall healthy, DLC2-mutant mice display enhanced angiogenic responses induced by matrigel and by tumor cells. Silencing of DLC2 in human ECs has reduced cell attachment, increased migration, and tube formation. These changes are rescued by silencing of RhoA, suggesting that the process is RhoA pathway dependent. These results indicate that DLC2 is not required for mouse development and normal vessel formation, but may protect mouse from unwanted angiogenesis induced by, for example, tumor cells

Original Article

Part I. Digitalis Ecg. in Goldberger\u27s Augmented Unipolar Limb Leads and Wilson\u27s Unipolar Chest Leads. There were analyzed the electrocardiograms of selected 37 cases which were scrupulously observed under the digitalis therapy on account of cardiac insufficiency. 1. P. a) Goldberger\u27s leads: The changes of P are generally not striking, only 2 cases showed the significant transformation in aV_R and aV_L, respectively. b) Wilson\u27s chest leads: The changes of P in V_1〜V_6 were found only in 4 cases. 2. Cardiac position and rotation. a) Goldberger\u27s leads: No more than 2 cases gave the disjtinct changes of the cardiac position in aV leads. b) At the early stage of digitalization the clockwise rotation was more frequently seen than the anticlockwise one. 3. ST. a) Goldberger\u27s leads: ST in aV_R were tend upward and ST in aV_F downward. ST in aV_L was either raised or lowered according to the cardiac position, but these changes were for the most part within normal limits. b) Wilson\u27s chest leads: Except for the extreme right ventricular strain curve, the digitalis ST depression was markedly observed in those leads which showed the largest upward deflection of QRS. Digitalis depresses ST of the levogram, and elevates ST of the dextrogram. However both in the excessive right ventricular strain curve and in the case with vivid Halb-seiten Effekt, digitalis does not raise ST of the dextrogram. 4. T. a) Goldberger\u27s leads: T in aV_F relatively often decreases in its positivity, becomes negative, and increases in its negativity. The characteristic changes due to digitalization are not clearly recognized in aV_R and aV_L. b) Wilson\u27s chest leads: T frequently decreases in its positivity, becomes negative or diphasic, and increases in its negativity. These changes are in special measure repeatedly found in the levogram. 5. Under the digitalization ventricular premature beats, auricular flutter and fibrillation appeared in several cases. Ventricular bigeminy and atrioventricular block were observed in each of two cases.On the contrary, there were found some cases in which the digitalization extinguished ventricular extrasystoles or bigeminy and auricular fibrillation persisted so long. Even in the presence of the ventricular bigeminy which is as a rule considered to be the indication to stop the digitalis use, yet digitalis can be administered under the closed notice. 6. Among 25 cases which showed sinus full rhythm, the prolongation of PR complicated with ST depression was observed in 6 cases (24 %). 7. Among 36 cases in which QT was estimated satisfactorily, the shortening of QT was found in 17 cases (47 %); 59 % of cases with shortened QT were accompanied by ST depression. 8. The digitalis bradycardia was recognized in 18 cases (49 %) and 65 % of bradycardic cases showed ST depression. 9. In the electrocardiograms of 7 cases suffered from the side effects of digitalis, i. e. vomitting, visual disturbance and so on, there could be often found arrhythmia and distinguished ST depression. The outburst of clinical side, effects was preceded by the clear-cut ST depression in two cases, so that it may possibly be taken the onset of the remarkable ST depression granted for an alarming sign of the threatening side effects. 10. The characteristic patterns of digitalis ecg. can be recognized even in the cases with digitalis refractoriness, the extent of such changes is, however, generally less striking and becomes as slighter as near death. Part II. Experimental Studies on so-called Digitalis Ecg. The experiments were carried on the dog\u27s hearts which were relatively resistive against digitalis Cdorsal fixation, isomytal anesthesia). a) the drip infusion of 1.0 mg of Strophosid intravenously. b) 5 times of the intravenous injections of 0.25 mg of Strophosid every 20 minutes. c) 3 times of the intravenous injection of 0.6 mg of Digicorin (AD-1), in total 1.8 mg. d) the intravenous injection of 1.0 mg of Acetylcholine before and after 1.8 mg of Digicorin.e) 2 times of the intravenous injection of 0.25 mg of Strophosid after the injection of 3.6 mg of Digicorin intravenously. f) the intravenous injection of 300 mg of Pronestyl at the event ventricular tachycardia due to over dosage of digitalis. The timepoint of every observation after the various digitalis injections is always the same; at each observation, besides registration of ecg., blood pressure and respiration, Wezler\u27s analysis was performed. 1) Either Strophosid or Digicorin, which is the limit of calculated therapeutic dosage, do not bring ST-T depression, whereas the calculated toxic doses of two drugs lower ST-T distinctly. There are found some cases in which the extrasystoles are preceded by the appearance of ST-T depression; therefore it cannot be concluded that changes of ST-T pattern can be possible for guide of the digitalis bioassay. 2) In the cases injected with Strophosid fractionatedly, ST-T depression can be recognized earlier at the smaller dosis than that in the cases treated by the drip intravenous infusion. Undiluted Strophosid does often elevate the blood pressure, chiefly due to increase in output. 3) The negative chronotropic action of both Strophosid and Digicorin is more or less weak. 4) The stimulation immediately after the cervical vago-sympathectomy prolongs PR, moreover occasionally elicits atrioventricular dissociation. 5) Even in the toxic stage of Strophosid the essential pattern of carotid sinus pressor reflex can be observed, although the degree \u27of reflexibility becomes smaller than that before the injection, and the reflex tachycardia becomes more vague. From these results it may be safe to say that the effect of reflexly augmented sympathicotonia by means of Hering\u27s second stimulation is difficult to take place because of the inhibitory vagal action of Strophosid. 6) The intravenous injection, of 1.0 mg of Acetylcholine administered before the use of Digicorin lowers the blood pressure range abruptly, and there develops apnea instantly after temporal hyperpnea.Electrocardiographically after ventricular arrest due to atrioventricular block followed tachycardic auricular impure flutter, there occured initially bradicardic, thereafter tachycardic auricular fibrillation, sinus complete rhythm, temporal atrioventricular dissociation in turn untill the complete sinus rhythm was recovered. The tachycardia which breaks out at the beginning, is considered to depend upon sinocarotid or cardioaortic chemoreceptor reflex, whereas the intravenous injection of 1.0 mg of Acetylcholine after Digicorin does not cause such an initial tachycardia, so that it may be appropriate to say that Digicorin does exert influence upon these reflex arcs. 7) The intravenous injection of Acetylcholine after application of Digicorin reveals quite the same extent of the reactivity with merely one half dosis, therefore it may be concluded that Digicorin is sure to promote the vagal tonisity. 8) The intravenous injection of Acetylcholine after the administration of Tropin brings out the inverse reaction of blood pressure, whereas the hyperventilation of short duration appears. The former phenomenon may be concerned with suppression of muscarinlike action of Acetylcholine, the latter with the deficiency of the paralytic action against visceroafferent fibre. 9) After the saturation accomplished with Digicorin the intravenous injection of Strophosid depresses ST-T and further there occurs ventricular tachycardia. Even after the saturation of Digicorin, of which toxity is very slight, the injection of Strophosid proves dangerous. 10) After the, saturation by the application of Digicorin, the ventricular tachycardia due to the intravenous injection of Strophosid cannot be prevented with the administration of 300 mg of pronestyl intravenously, so the arterial depression develops. But there appeared the reduction of QRS interval which can be thought to be improvement of intraventricular conduction disturbance; therefore in such event Pronestyl proves necessary.11) All instances injected with Strophosid as above mentioned may show subendocardial haemorrhage which was observed more markedly in the outflow area beneath aortic valves than in the inflow area under mitral valves. The subendocardial haemorrhage lacked in inflammation histologically. The cases treated with the singular use of Digicorin do not show the subendocardial haemorrhage even if ST-T depressed remarkably

Probing onset of strong localization and electron-electron interactions with the presence of direct insulator-quantum Hall transition

We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall transition with increasing the perpendicular magnetic field. However, such a transition does not correspond to the onset of strong localization. The temperature dependences of the Hall resistivity and Hall conductivity reveal the importance of the electron-electron interaction effects to the observed transition in our study.Comment: 9 pages, 4 figure

Experimental Studies of Low-field Landau Quantization in Two-dimensional Electron Systems in GaAs/AlGaAs Heterostructures

By applying a magnetic field perpendicular to GaAs/AlGaAs two-dimensional electron systems, we study the low-field Landau quantization when the thermal damping is reduced with decreasing the temperature. Magneto-oscillations following Shubnikov-de Haas (SdH) formula are observed even when their amplitudes are so large that the deviation to such a formula is expected. Our experimental results show the importance of the positive magneto-resistance to the extension of SdH formula under the damping induced by the disorder.Comment: 9 pages, 3 figure

Insulator, semiclassical oscillations and quantum Hall liquids at low magnetic fields

Magneto-transport measurements are performed on two-dimensional GaAs electron systems to probe the quantum Hall (QH) effect at low magnetic fields. Oscillations following the Shubnikov-de Haas (SdH) formula are observed in the transition from the insulator to QH liquid when the observed almost temperature-independent Hall slope indicates insignificant interaction correction. Our study shows that the existence of SdH oscillations in such a transition can be understood based on the non-interacting model.Comment: 17 page

Integrin-mediated membrane blebbing is dependent on the NHE1 and NCX1 activities.

Integrin-mediated signal transduction and membrane blebbing have been well studied to modulate cell adhesion, spreading and migration^1-6^. However, the relationship between membrane blebbing and integrin signaling has not been explored. Here we show that integrin-ligand interaction induces membrane blebbing and membrane permeability change. We found that sodium-proton exchanger 1 (NHE1) and sodium-calcium exchanger 1 (NCX1) are located in the membrane blebbing sites and inhibition of NHE1 disrupts membrane blebbing and decreases membrane permeability change. However, inhibition of NCX1 enhances cell blebbing to cause cell swelling which is correlated with an intracellular sodium accumulation induced by NHE17. These data suggest that sodium influx induced by NHE1 is a driving force for membrane blebbing growth, while sodium efflux induced by NCX1 in a reverse mode causes membrane blebbing retraction. Together, these data reveal a novel function of NHE1 and NCX1 in membrane permeability change and blebbing and provide the link for integrin signaling and membrane blebbing

Ventricular divergence correlates with epicardial wavebreaks and predicts ventricular arrhythmia in isolated rabbit hearts during therapeutic hypothermia

INTRODUCTION: High beat-to-beat morphological variation (divergence) on the ventricular electrogram during programmed ventricular stimulation (PVS) is associated with increased risk of ventricular fibrillation (VF), with unclear mechanisms. We hypothesized that ventricular divergence is associated with epicardial wavebreaks during PVS, and that it predicts VF occurrence. METHOD AND RESULTS: Langendorff-perfused rabbit hearts (n = 10) underwent 30-min therapeutic hypothermia (TH, 30°C), followed by a 20-min treatment with rotigaptide (300 nM), a gap junction modifier. VF inducibility was tested using burst ventricular pacing at the shortest pacing cycle length achieving 1:1 ventricular capture. Pseudo-ECG (p-ECG) and epicardial activation maps were simultaneously recorded for divergence and wavebreaks analysis, respectively. A total of 112 optical and p-ECG recordings (62 at TH, 50 at TH treated with rotigaptide) were analyzed. Adding rotigaptide reduced ventricular divergence, from 0.13±0.10 at TH to 0.09±0.07 (p = 0.018). Similarly, rotigaptide reduced the number of epicardial wavebreaks, from 0.59±0.73 at TH to 0.30±0.49 (p = 0.036). VF inducibility decreased, from 48±31% at TH to 22±32% after rotigaptide infusion (p = 0.032). Linear regression models showed that ventricular divergence correlated with epicardial wavebreaks during TH (p<0.001). CONCLUSION: Ventricular divergence correlated with, and might be predictive of epicardial wavebreaks during PVS at TH. Rotigaptide decreased both the ventricular divergence and epicardial wavebreaks, and reduced the probability of pacing-induced VF during TH