Size effect in a percolation model of interconnect failure

The problem of interconnect failure is studied in the framework of percolation theory. The probability failure of a long interconnect due to statistical fluctuations of defects is found. It is demonstrated that two possible diapasons of length to width ratios exist. For extremely long wires, the percolation threshold is determined by rare accumulation of defects, breaking down the wire. For moderately long wires, the threshold concentration of defects is near the macroscopic percolation threshold. The lowering of threshold due to finite width of wire is found. The percolation threshold is found in a two-dimensional system, containing the individual vacancies and voids, caused by coalescence of vacancies.     

Nanomusical systems visualized and controlled in 4D electron microscopy

Nanomusical systems, nanoharp and nanopiano, fabricated as arrays of cantilevers by focused ion beam milling of a layered Ni/Ti/Si(3)N(4) thin film, have been investigated in 4D electron microscopy. With the imaging and selective femtosecond and nanosecond control combinations, full characterization of the amplitude and phase of the resonant response of a particular cantilever relative to the optical pulse train was possible. Using a high repetition rate, low energy optical pulse train for selective, resonant excitation, coupled with pulsed and steady-state electron imaging for visualization in space and time, both the amplitude on the nanoscale and resonance of motion on the megahertz scale were resolved for these systems. Tilting of the specimen allowed in-plane and out-of-plane cantilever bending and cantilever torsional motions to be identified in stroboscopic measurements of impulsively induced free vibration. Finally, the transient, as opposed to steady state, thermostat effect was observed for the layered nanocantilevers, with a sufficiently sensitive response to demonstrate suitability for in situ use in thin-film temperature measurements requiring resolutions of <10 K and 10 μm on time scales here mechanically limited to microseconds and potentially at shorter times.     

C6 modification of the pyridinone core of thrombin inhibitor L-374,087 as a means of enhancing its oral absorption

1 (L-374,087) is a potent, selective, efficacious, and orally bioavailable thrombin inhibitor that contains a core 3-amino-2-pyridinone moiety. Replacement of the C6 pyridinone methyl group of 1 by a propyl group gave 5 (L-375,052), which retained all the excellent properties of 1, and also yielded higher plasma levels after oral dosing in dogs and rats.     

Vacuous jaw movements in rats induced by acute reserpine administration: interactions with different doses of apomorphine

Two experiments were conducted to study the vacuous jaw movements induced in rats by acute administration of the monoamine-depleting agent reserpine. In the first experiment, different doses of reserpine (1.25, 2.5, and 5.0 mg/kg) were assessed for their ability to induce vacuous jaw movements. Acute administration of reserpine induced a dose-related increase in vacuous jaw movements, with the two highest doses being significantly different from the vehicle control. In the second experiment, interactions between 5.0 mg/kg reserpine and the dopamine agonist apomorphine were investigated. Coadministration of reserpine with the lowest dose of apomorphine (0.1 mg/kg) significantly increased vacuous jaw movements relative to reserpine alone. The two higher doses of apomorphine (0.5 and 1.0 mg/kg) significantly decreased vacuous jaw movements in reserpine-treated rats. These results demonstrate that vacuous jaw movements are induced by acute reserpine treatment in a dose-related manner. In addition, the interactions with apomorphine suggest that vacuous jaw movements are stimulated by decreases in dopamine release produced by low doses of apomorphine that are thought to have mainly presynaptic actions, but that these movements are decreased by higher doses of apomorphine that are known to act postsynaptically.     

Biological profile of L-745,870, a selective antagonist with high affinity for the dopamine D4 receptor

L-745,870,(3-([4-(4-chlorophenyl)piperazin-1-yl]methyl)-1H- pyrollo[2,3-b] pyridine, was identified as a selective dopamine D4 receptor antagonist with excellent oral bioavailability and brain penetration. L-745,870 displaced specific binding of 0.2 nM [3H] spiperone to cloned human dopamine D4 receptors with a binding affinity (Ki) of 0. 43 nM which was 5- and 20-fold higher than that of the standard antipsychotics haloperidol and clozapine, respectively. L-745,870 exhibited high selectivity for the dopamine D4 receptor (>2000 fold) compared to other dopamine receptor subtypes and had moderate affinity for 5HT2, sigma and alpha adrenergic receptors(IC50 < 300 nM). In vitro, L-745,870 (0.1-1 microM) exhibited D4 receptor antagonist activity, reversing dopamine (1 microM) mediated 1) inhibition of adenylate cyclase in hD4HEK and hD4CHO cells; 2) stimulation of [35S] GTPgammaS binding and 3) stimulation of extracellular acidification rate, but did not exhibit any significant intrinsic activity in these assays. Although standard antipsychotics increase dopamine metabolism or plasma prolactin levels in rodents, L-745,870 (相似文献   

Some Aspects of Microstructure Damage to Cr–Mo–V Rotor Steel as a Consequence of Extremely Long Operation

Technical Physics Letters - The observed plasticity degradation of Cr–Mo–V heat resistant steel as a consequence of more than 20-year operation at 510 and 300°C is caused by an...     

Use-dependent effects of the class III antiarrhythmic agent NE-10064 (azimilide) on cardiac repolarization: block of delayed rectifier potassium and L-type calcium currents

We studied the effects of NE-10064 (azimilide), a new antiarrhythmic agent reported to be a selective blocker of the slowly activating component of the delayed rectifier, IKs. In ferret papillary muscles, NE-10064 increased effective refractory period (ERP) and decreased isometric twitch tension in a concentration-dependent manner (0.3-30 microM). Increases in ERP showed reverse use-dependence, and were greater at 1 than at 3 Hz. In contrast, changes in tension were use dependent, with larger decreases observed at 3 than at 1 Hz. In guinea pig ventricular myocytes, NE-10064 (0.3-3 microM) significantly prolonged action potential duration (APD) at 1 Hz. At 3 Hz, NE-10064 (0.3-1 microM) increased APD only slightly, and at 10 microM decreased APD and the plateau potential. NE-10064 potently blocked the rapidly activating component of the delayed rectifier, IKr (IC50 0.4 microM), and inhibited IKs (IC50 3 microM) with nearly 10-fold less potency. NE-10064 (10 microM) did not block the inward rectifier potassium current (IKl). NE-10064 (10 microM) blocked the L-type calcium current (ICa) in a use-dependent manner; block was greater at 3 than at 1 Hz. We conclude that (a) NE-10064's block of potassium currents is relatively selective for IKr over IKs, (b) NE-10064 inhibits ICa in a use-dependent fashion, and (c) NE-10064's effects on ERP and tension in papillary muscle as well as APD and action potential plateau level in myocytes may be explained by its potassium and calcium channel blocking properties.