PLANAR COPPER PLATING AND ELECTROPOLISHING TECHNIQUES

Electrochemical mechanical deposition (ECMD) is a novel technique that has the ability to deposit planar conductive films on non planar substrate surfaces. This technique involves electrochemical deposition (ECD) while simultaneously polishing the substrate surface. Preferential deposition of the conductor into the cavities on the substrate surface may be achieved through two different mechanisms. The first mechanism is more mechanical in nature and it involves material removal from the top surface. The second mechanism is more chemical in nature, and it involves enhancing the deposition into the cavities where mechanical sweeping does not reach and reducing deposition onto surfaces that are swept. In this study we demonstrate that in an ECMD process, low-pressure mechanical sweeping of the wafer surface during copper plating can establish a differential in the activity of the organic accelerator species between the surface and the cavity regions of the substrate and thus give rise to bottom-up filling in even the lowest aspect-ratio cavities. Planar layers obtained by the ECMD technique have been successfully employed in an electrochemical polishing technique for stress-free removal of Cu.     

LTP of AMPA and NMDA receptor-mediated signals: evidence for presynaptic expression and extrasynaptic glutamate spill-over

We have addressed the expression of long-term potentiation (LTP) in hippocampal CA1 by comparing AMPA and NMDA receptor-(AMPAR- and NMDAR-) mediated postsynaptic signals. We find that potentiation of NMDAR-mediated signals accompanies LTP of AMPAR-mediated signals, and is associated with a change in variability implying an increase in quantal content. Further, tetanic LTP of NMDAR-mediated signals can be elicited when LTP of AMPAR-mediated signals is prevented. We propose that LTP is mainly expressed presynaptically, and that, while AMPARs respond only to glutamate from immediately apposed terminals, NMDARs also sense glutamate released from terminals presynaptic to neighboring cells. We also find that tetanic LTP increases the rate of depression of NMDAR-mediated signals by the use-dependent blocker MK-801, implying an increase in the glutamate release probability. These findings argue for a presynaptic contribution to LTP and for extrasynaptic spill-over of glutamate onto NMDARs.     

C–(N)–S–H and N–A–S–H gels: Compositions and solubility data at 25°C and 50°C

Calcium silicate hydrates containing sodium [C–(N)–S–H], and sodium aluminosilicate hydrates [N–A–S–H] are the dominant reaction products that are formed following reaction between a solid aluminosilicate precursor (eg, slags, fly ash, metakaolin) and an alkaline activation agent (eg NaOH) in the presence of water. To gain insights into the thermochemical properties of such compounds, C–(N)–S–H and N–A–S–H gels were synthesized with compositions: 0.8≤Ca/Si≤1.2 for the former, and 0.25≤Al/Si≤0.50 (atomic units) for the latter. The gels were characterized using thermogravimetric analysis (TGA), scanning electron microscopy with energy‐dispersive X‐ray microanalysis (SEM‐EDS), and X‐ray diffraction (XRD). The solubility products (K_S0) of the gels were established at 25°C and 50°C. Self‐consistent solubility data of this nature are key inputs required for calculation of mass and volume balances in alkali‐activated binders (AABs), and to determine the impacts of the precursor chemistry on the hydrated phase distributions; in which, C–(N)–S–H and N–A–S–H compounds dominate the hydrated phase assemblages.     

Intracoronary administration of the combined fibrinolytic therapy a in patient with acute myocardial infarction and end-stage coronary heart disease - a case report]

Classical thrombolytic treatment in acute myocardial infarction is able to reach reperfusion in 60-80% of patients, however in 5-10% of cases reoclusion occurs. Primary percutaneous coronary intervention (PCI) offers the potential for a higher rate of reperfusion and a lower rate of bleeding events. Recently, advances in platelet inhibition and PCI procedures have led to the combination of all the approaches. Facilitated PCI or the use of elective PCI after pharmacological reperfusion therapy can combine the best aspects of thrombolysis and mechanical revascularization in acute myocardial infarction. However, in some cases PCI cannot be performed. This paper describes a patient with acute myocardial infarction successfully treated with intracoronary infusion of alteplase and GP IIb/IIIa inhibitor.     

Fast RCS pattern fill using AWE technique

An extrapolation technique is adapted to predict the monostatic radar cross-section (RCS) pattern from a few pattern value calculations. This asymptotic waveform evaluation (AWE) approach eliminates a need to resolve the system when an iterative solver is employed. A three-dimensional application is considered to demonstrate the accuracy of the technique     

Response of thalamocortical neurons to hypoxia: a whole-cell patch-clamp study

The effect of hypoxia (3-4 min of 95% N2, 5% CO2) on thalamocortical (TC) neurons was investigated using the whole-cell patch-clamp technique in rat dorsal lateral geniculate nucleus slices kept submerged at 32 degreesC. The predominant feature of the response of TC neurons to hypoxia was an increase in input conductance (DeltaGN = 117 +/- 15%, n = 33) that was accompanied by an inward shift in baseline holding current (IBH) at -65 and -57 mV (DeltaIBH = -45 +/- 6 pA, n = 18, and -25 +/- 8 pA, n = 33, respectively) but not at -40 mV. The hypoxia-induced increase in GN (as well as the shift in IBH) was abolished by procedures that are known to block Ih, i.e., bath application of 4-(N-ethyl-N-phenylamino)-1, 2-dimethyl-6-(methylamino)-pyrimidinium chloride (100-300 microM) (DeltaGN = 5 +/- 13%, n = 11) and CsCl (2-3 mM) (DeltaGN = 16 +/- 16%, n = 5), or low [Na+]o (DeltaGN = 10 +/- 10%, n = 5), whereas bath application of BaCl2 (0.1-2.0 mM) had no significant effect (DeltaGN = 128 +/- 14%, n = 8). The hypoxic response was also abolished in low [Ca+2]o (DeltaGN = 25 +/- 16%, DeltaIBH = -6 +/- 8 pA, n = 13), but was unaffected by recording with electrodes containing EGTA (10 mM), BAPTA (10-30 mM), Cs+, or Cl-, as well as in the presence of external tetraethylammonium and 4-aminopyridine. Furthermore, preincubation of the slices with botulinum toxin A (100 nM), which is known to reduce Ca2+-dependent transmitter release, blocked the hypoxic response (DeltaGN = -3 +/- 15%, DeltaIBH = 10 +/- 5 pA, n = 4). We suggest that a positive shift in the voltage-dependence of Ih and a change in its activation kinetics, which transforms it into a fast activating current, may be responsible for the hypoxia-induced changes in GN and IBH, probably via an increase in Ca+2-dependent transmitter release.     

Frequency-selective surfaces to enhance performance of broad-band reconfigurable arrays

We present a novel frequency-selective surface (FSS) design aimed at enhancing the performance of broad-band reconfigurable antenna apertures. In particular, reconfigurable printed dipole arrays are examined in the presence of a multilayer FSS. Of particular interest is the design of FSS structures whose reflection coefficient has prespecified phase response over a broad set of frequencies. Previous FSSs primarily considered designs on the basis of the reflection coefficient amplitude and were intended for radome applications rather than substrates. Designing FSSs subject to phase requirements is seen to require some compromise in the magnitude. Broad-band requirements also present us with a need for noncommensurate FSS designs.     

Design optimization of conformal antennas by integrating stochasticalgorithms with the hybrid finite-element method

Previous work in antenna optimization has primarily focused on applications of optimization algorithms in conjunction with problem-specific or semi-analytic tools. However, previous developments in fast algorithms now offer the possibility of designs and moreover allow for full flexibility in material specification across three dimensions. As an example, this paper combines genetic algorithms (GA) and simulated annealing (SA) with fast hybrid finite-element boundary integral simulations to develop full three-dimensional (3-D) antenna designs using shape, topology, as well as material optimization. To illustrate these optimization methods as well as compare between GA and SA, three different antenna designs are considered. First, a folded-slot antenna is optimized for broad-band performance, followed by an irregular-shaped dual-band antenna design. As a third design, which combines shape and material optimization, a bandgap substrate is designed to substantially increase the bandwidth of a patch residing on the optimized substrate     

In vitro and in vivo evaluation of the effects of demineralized bone matrix or calcium sulfate addition to polycaprolactone–bioglass composites

The objective of this study was to improve the efficacy of polycaprolactone/bioglass (PCL/BG) bone substitute using demineralized bone matrix (DBM) or calcium sulfate (CS) as a third component. Composite discs involving either DBM or CS were prepared by compression moulding. Bioactivity of discs was evaluated by energy dispersive X-ray spectroscopy (ESCA) and scanning electron microscopy (SEM) following simulated body fluid incubation. The closest Calcium/Phosphate ratio to that of hydroxyl carbonate apatite crystals was observed for PCL/BG/DBM group (1.53) after 15 day incubation. Addition of fillers increased microhardness and compressive modulus of discs. However, after 4 and 6-week PBS incubations, PCL/BG/DBM discs showed significant decrease in modulus (from 266.23 to 54.04 and 33.45 MPa, respectively) in parallel with its highest water uptakes (36.3 and 34.7%). Discs preserved their integrity with only considerable weight loss (7.5–14.5%) in PCL/BG/DBM group. In vitro cytotoxicity tests showed that all discs were biocompatible. Composites were implanted to defects on rabbit humeri. After 7 weeks, new tissue formation and mineralization at bone-implant interface were observed for all implants. Bone mineral densities at interface were higher than that of implant site and negative controls (defects left empty) but lower than healthy bone level. However, microhardness of implant sites was higher than in vitro results indicating in vivo mineralization of implants. Addition of DBM or CS resulted with higher microhardness values at interface region (ca. 650 μm from implant) compared to PCL/BG and negative control. Histological studies revealed that addition of DBM enhanced bone formation around and into implant while CS provided cartilage tissue formation around the implant. From these results, addition of DBM or CS could be suggested to improve bone healing efficacy of PCL/BG composites.