An all-analog expandable neural network LSI with on-chipbackpropagation learning

This paper proposes an all-analog neural network LSI architecture and a new learning procedure called contrastive backpropagation learning. In analog neural LSI's with on-chip backpropagation learning, inevitable offset errors that arise in the learning circuits seriously degrade the learning performance. Using the learning procedure proposed here, offset errors are canceled to a large extent and the effect of offset errors on the learning performance is minimized. This paper also describes a prototype LSI with 9 neurons and 81 synapses based on the proposed architecture which is capable of continuous neuron-state and continuous-time operation because of its fully analog and fully parallel property. Therefore, an analog neural system made by combining LSI's with feedback connections is promising for implementing continuous-time models of recurrent networks with real-time learning     

Prolonged survival of rat liver allografts transfected with Fas ligand-expressing plasmid

BACKGROUND: Transplantation of Fas ligand (FasL) gene-transfected tissues can have opposite effects. For example, cotransplantation of pancreas islets with myoblasts transfected with FasL-expressing plasmid vector (pFasL) prevented graft rejection, whereas the expression of FasL directly within islets using adenovirus vector led to graft destruction. It was also reported that FasL expression on pancreas islets led to neutrophilic infiltration and rapid destruction of the islets. From these results, overexpression of FasL in transfected tissues may lead directly to self destruction through an autocrine Fas-FasL pathway or graft destruction through neutrophil recruitment. To date there have been no reports of successful transplantation of FasL gene-transfected solid organs. METHODS: Rat pFasL was transfected at a dose of 90, 180, 270, or 360 microg into rat liver with an inactivated hemagglutinating virus of Japan conjugated to liposome vesicles (HVJ-liposome), and the gene-transfected livers were transplanted to allogeneic rats. RESULTS: In 18 rats transfected with 180 microg of pFasL, 14 (78%) did not develop fulminant hepatitis. FasL-mRNA was detected in these livers at 3, 5, 7, and 14 days after transfection. The expression of FasL protein was also observed in the transfected liver, and the transfection rate by this method was 11.1+/-1.9%. The livers were then transplanted to allogeneic recipients, resulting in significant (P<0.01) prolonged recipient survival times. Histological observation showed that the pFasL-transfected liver allografts caused apoptotic cell death in infiltrating activated T cells. In contrast, transfection of pFasL higher than 180 microg resulted in lethal hepatitis in all rats, and its low dose (90 microg) did not induce the hepatitis or prolong recipient survival. CONCLUSION: Our results indicate that rat liver allografts can be protected to host immune responses by an adequate level (approximately 10%) of FasL expression in the livers using HVJ-liposome incorporating pFasL.     

Schottky diode design for low-voltage rectification

Barrier height and impurity concentration of a power Schottky diode are optimized for maximum rectifying efficiency in DC-DC converter operation. An optimum barrier-height-impurity-concentration combination is calculated for a given output voltage and diode temperature. For a 1.5 – 2 V output converter, the optimum combination is found to be 17 kT/q and 1.5 × 10¹⁶ cm^?3. Based on the theoretical prediction, titanium- and hafnium-barrier diodes were fabricated as suitable diodes for low-voltage converters and compared with conventionally used molybdenum-barrier diodes. In the experiment on a 2-V output DC-DC converter, the new diodes show higher efficiency than molybdenum diodes at up to 85°C. They are fit for use in encapsulated converters because of their smaller heat generation.     

Internal stenting of the hepaticojejunostomy and pancreaticojejunostomy in patients undergoing pancreatoduodenectomy to promote earlier discharge from hospital

Arterial compliance and central blood volume were evaluated in obese and nonobese patients with and without hypertension. Arterial compliance was lower in the hypertensive group, although obese subjects, regardless of their blood pressure, had higher arterial compliance. The ratio of central blood volume to total blood volume was highest in hypertensive patients, whether obese or lean, indicating increased venoconstriction.     

Graphene/Half-Metallic Heusler Alloy: A Novel Heterostructure toward High-Performance Graphene Spintronic Devices

Graphene-based vertical spin valves (SVs) are expected to offer a large magnetoresistance effect without impairing the electrical conductivity, which can pave the way for the next generation of high-speed and low-power-consumption storage and memory technologies. However, the graphene-based vertical SV has failed to prove its competence due to the lack of a graphene/ferromagnet heterostructure, which can provide highly efficient spin transport. Herein, the synthesis and spin-dependent electronic properties of a novel heterostructure consisting of single-layer graphene (SLG) and a half-metallic Co₂Fe(Ge_0.5Ga_0.5) (CFGG) Heusler alloy ferromagnet are reported. The growth of high-quality SLG with complete coverage by ultrahigh-vacuum chemical vapor deposition on a magnetron-sputtered single-crystalline CFGG thin film is demonstrated. The quasi-free-standing nature of SLG and robust magnetism of CFGG at the SLG/CFGG interface are revealed through depth-resolved X-ray magnetic circular dichroism spectroscopy. Density functional theory (DFT) calculation results indicate that the inherent electronic properties of SLG and CFGG such as the linear Dirac band and half-metallic band structure are preserved in the vicinity of the interface. These exciting findings suggest that the SLG/CFGG heterostructure possesses distinctive advantages over other reported graphene/ferromagnet heterostructures, for realizing effective transport of highly spin-polarized electrons in graphene-based vertical SV and other advanced spintronic devices.     

PH-induced structure change of poly(vinyl alcohol) hydrogel crosslinked with poly(acrylic acid)

The structure of the hydrogel of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) was investigated by small angle X-ray scattering (SAXS) of synchrotron radiation. A physically crosslinked blend gel, which was prepared by repetitive freezing and thawing of an aqueous solution of PVA and PAA, could be chemically crosslinked by esterfication of PVA with PAA even in the hydrogel state. The chemical crosslinking induced the destruction of physical crosslinks into a folded structure, indicating that the chemical crosslinking proceeds at the sites around the physical crosslinks that contain PVA and PAA in much higher concentration than other portion of the gel. The pH-induced structure changes of the PVA hydrogels, chemically crosslinked with poly(acrylic acid) (PAA) were investigated by SAXS on the samples of various chemical crosslinking time. The gels were shrunk at pH4, and swollen at pH8. The results of SAXS showed, that the Porod slope changed with chemical crosslinking time from -3.5 to ?2.9 at pH4, and from ?2.9 to ?2.4 at pH8. The results suggest that a folded structure as a structural domain, which is characterized by fractally rough interface, tends to change into the structure that corresponds to percolation cluster, particularly at pH8. The gels immersed in pH8 showed a remarkable structure change accompanying swelling. The results revealed that a conformational change of PAA chains, induced by the pH change, can be explained by the presence of a structural domain in the gel network, where both PVA chains and PAA chains get entangled and partially form a interpenetrating polymer network(IPN).     

Different behavior between Pt and Pd catalysts in the hydrogenolysis of cyclohexanediones and hydroxycyclohexanones

Hydrogenolysis reactions of cyclohexanediones, hydroxycyclohexanones, and some related alicyclic ketones were studied over Pt, Pd, Ir, and Rh catalysts at atmospheric hydrogen pressure in t-butyl alcohol as a solvent. Pt and Pd had high catalytic activities for the hydrogenolysis of carbon-oxygen bonds. However, Ir and Rh scarcely had any activity unless 1,3-cyclohexanedione and 3-hydroxycyclohexanone were involved. The mechanisms of the hydrogenolysis differed with Pt and Pd. In the hydrogenation of 4-methoxycyclohexanone, Pt afforded cyclohexyl methyl ether as the hydrogenolysis product; while Pd afforded cyclohexanone, which was then hydrogenated to cyclohexanol. Thus Pt cleaved the carbon-oxygen double bond, and Pd cleaved the carbon-oxygen single bond. Deuterolysis of cyclohexanone and 4-methoxycyclohexanone on Pt gave mainly d₂ species of cyclohexane and cyclohexyl methyl ether as the hydrogenolysis products. This indicated that the carbon-oxygen double bonds were directly cleaved to yield methylene groups on Pt. Almost of all 3-hydroxycyclohexanone was hydrogenolyzed to cyclohexanone on Pd; whereas cyclohexanone as well as cyclohexanol was not hydrogenolyzed at all. In the case of Pd, the carbon-oxygen single bond was cleaved when it was activated by formation of π-oxoallyl adsorbed species on the catalyst at the carbon-oxygen double bond.