Investigation of forming-gas annealed CeO<Subscript>2</Subscript> thin film on GaN

The effects of post-deposition annealing temperatures (400, 600, 800, and 1,000°C) in forming gas (95% N₂ + 5% H₂) ambient on metal–organic decomposed cerium oxide (CeO₂) thin films deposited on n-type GaN substrate had been investigated. The occurrence of CeO₂ phase transformation was reported and presence of CeO₂, α-Ce₂O₃, and β-Ga₂O₃ had been detected, depending on the annealing temperature. As the annealing temperature increased, grain size and microstrains of CeO₂ films were, respectively, increased and reduced. Metal–oxide–semiconductor characteristics of the annealed samples were systematically investigated. The highest dielectric breakdown field was perceived by sample annealed at 400°C due to the reduction of semiconductor–oxide interface trap density and effective oxide charge.     

Sub-5 keV electron-beam lithography in hydrogen silsesquioxane resist

We fabricated 9-30 nm half-pitch nested Ls and 13-15 nm half-pitch dot arrays, using 2 keV electron-beam lithography with hydrogen silsesquioxane (HSQ) as the resist. All structures with 15 nm half-pitch and above were fully resolved. We observed that the 9 and 10-nm half-pitch nested Ls and the 13-nm-half-pitch dot array contained some resist residues. We obtained good agreement between experimental and Monte-Carlo-simulated point-spread functions at energies of 1.5, 2, and 3 keV. The long-range proximity effect was minimal, as indicated by simulated and patterned 30 nm holes in negative-tone resist.     

Effects of the composition of sputtering target on the stability of InGaZnO thin film transistor

In this study, we investigated the electrical characteristics and the stability of amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) from the viewpoint of active layer composition. Active layers of TFTs were deposited by r.f. sputtering. Two kinds of sputtering targets, which have different compositional ratios of In:Ga:Zn, were used to make variations in the active layer composition. All the fabricated IGZO TFTs showed more excellent characteristics than conventional amorphous silicon TFTs. However, in accordance with the Ga content, IGZO TFTs showed somewhat different electrical characteristics in values such as the threshold voltage and the field effect mobility. The device stability was also dependent on the Ga content, but had trade-off relation with the electrical characteristics.     

Frequent loss of heterozygosity and three critical regions on the short arm of chromosome 8 in ovarian adenocarcinomas

BACKGROUND: Familial arteriolar tortuosity is an autosomal dominant disorder affecting the retinal arterioles. OBJECTIVES: To report a pedigree with this disorder and describe a systemic workup to determine whether this vascular abnormality is limited to the eye. RESULTS: A 58-year-old woman referred for retinal hemorrhages was found to have retinal arteriolar tortuosity of both eyes, especially in the macular area. Her 63-year-old brother had a history of retinal hemmorhages beginning at age 18 years and had similar fundoscopic examination findings. The proband had an extensive systemic workup, including magnetic resonance imaging, and cardiac and renal angiography, that failed to demonstrate any other sequelae of this inherited ocular syndrome. However, each member of the family expressing this phenotype did have hypertension. CONCLUSION: Inherited retinal arteriolar tortuosity is an autosomal dominant disorder limited to the eye, at least in this pedigree, within the sensitivity of the systemic workup we used.     

ECoDE – An Environmental Component Design Evaluation Tool

. Mass consumerism has brought about increasing consumption of non-renewable natural resources and manufactured goods, and is creating a waste disposal problem of unprecedented magnitude in the process. In the long run, sustainable manufacturing is only attainable given environmentally responsible product design. There are many tools for the analysis of the impact of manufactured products on the environment, but they do not offer a level of detail sufficient to identify environmentally offensive components in the product. This paper discusses a computer-based design evaluation tool, ECoDE, developed for assessing the environmental impact of components in a product. ECoDE makes use of the Analytical Hierarchy Process to compare each criterion, and rank them in an ascending order of relative significance. The types of materials used, their costs, manufacturing processes, reliability, and ease of access for disassembly are some of the key assessment criteria being considered. Finally, a multi-attribute (or criteria) rating technique is used to compute the scores against each of the criteria for both components and the overall product. The larger the score, the less severe the impact of the component or product on the environment. A discussion is then made on an evaluation test case conducted by ECoDE. Preliminary tests have found that ECoDE is able to calculate the least environmentally friendly component and highlight its likely causes.     

Changes in birefringence as markers of thermal damage in tissues

Light microscopy using polarized transmission illumination of routinely stained histologic sections shows changes of the native birefringence of certain tissue constituents when heated by laser irradiation or electrosurgical current. The naturally occurring birefringence of cardiac muscle disappears permanently when the muscle is frozen, thawed, and heated to temperatures in excess of 42 degrees C in vitro. This loss of birefringence is produced with temperatures at which other morphologic thermal changes are hard to detect; thus, it is a low-temperature tissue marker which can be used to observe the extent of thermal damage in tissues. Partial loss of the native birefringence of collagen occurs in canine urinary bladder coagulated by laser irradiation and pericardium heated with electrodes. In addition, thermally coagulated collagens have variable birefringence color shifts when compared to the adjacent unaffected collagens in stained histologic sections. The gradual birefringence color changes are seen at tissue temperatures higher than those at which the thermally induced hyalinization (coagulation) of collagen usually occurs (about 60-70 degrees C), but below those at which carbonization is seen (200+ degrees C). Birefringence changes can be measured to test mathematical models of thermal damage necessary for development of dosimetry models in medical applications of laser irradiation.     

Efficient mixing of viscoelastic fluids in a microchannel at low Reynolds number

In this paper, we examined mixing of various two-fluid flows in a silicon/glass microchannel based on the competition of dominant forces in a flow field, namely viscous/elastic, viscous/viscous and viscous/inertial. Experiments were performed over a range of Deborah and Reynolds numbers (0.36 < De < 278, 0.005 < Re < 24.2). Fluorescent dye and microshperes were used to characterize the flow kinematics. Employing abrupt convergent/divergent channel geometry, we achieved efficient mixing of two-dissimilar viscoelastic fluids at very low Reynolds number. Enhanced mixing was achieved through elastically induced flow instability at negligible diffusion and inertial effects (i.e. enormous Peclet and Elasticity numbers). This viscoelastic mixing was achieved over a short effective mixing length and relatively fast flow velocities.     

Isolation and identification of the cDNA encoding the pheromone biosynthesis activating neuropeptide and additional neuropeptides in the oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae)

The present study is concerned with cloning and characterizing Has-PBAN cDNA which is 756 nucleotides long, isolated from the brain and suboesophageal ganglion complex (Br-Sg) of Helicoverpa assulta adults. The 194-amino acid sequence deduced from this cDNA possessed the proteolytic endocleavage sites to generate multiple peptides. From the processing of the prepro-hormone, it can be predicted that the cDNA has a PBAN domain with 33 amino acids and four additional peptide domains: 24 amino acid-, 7 amino acid-, 18 amino acid- and 8 amino acid-long sequences, with FXPR (or K) L (X = G, T or S) amidated at their C-termini. The amino acid sequence of all five predicted peptides, including the PBAN, are identical to that of Helicoverpa zea (Raina, A.K., Jaffe, H., Kempe, T.G., Keim, P., Blacher, R.W., Fales, H.M., Riley, C.T., Klun, J.A., Ridgway, R.L., Hayes, D.K., 1989. Identification of a neuropeptide hormone that regulates sex pheromone production in female moths. Science 244, 796-798 and Ma, P.W.K., Knipple, D.C., Roelofs, W.L., 1994. Structural organization of the Helicoverpa zea gene encoding the precursor protein for pheromone biosynthesis-activating neuropeptide and other neuropeptides. Proc. Natl. Acad. Sci., U.S.A. 91, 506-510). A single mRNA species corresponding to the size of Has-PBAN cDNA was detected from the Br-Sg of 1-3-day old female and male adults, and their expression was also at a similar level. Pheromone production was induced upon injection of female or male Br-Sg extracts or synthetic PBAN into the haemocoel of decapitated 1-3-day old female adults during the photophase when they are not supposed to produce pheromone. From these results, H. assulta adult females seem to use their own PBAN for regulating sex pheromone biosynthesis. Functions of the four other peptides ending with FXPR (or K) L in the Has-PBAN cDNA and of the male PBAN remain to be elucidated.     

Effect of interfacial crosslinking on miscibility behavior between isocyanate‐functionalized poly(n‐butyl methacrylate) particles and carboxylic alkali‐soluble resin

The effect of interfacial crosslinking on miscibility behavior in blend systems of isocyanate‐functionalized poly(n‐butyl methacrylate) (PBMA) and a carboxylic alkali‐soluble resin, poly(styrene/alpha‐methylstyrene/acrylic acid) (SAA), was studied with different dimethyl meta‐isopropenyl benzyl isocyanate (TMI) concentrations. For the blend films of pure PBMA and SAA, both theoretical analysis and direct observation showed immiscibility between PBMA and SAA. For the blend systems of isocyanated PBMA and SAA, Fourier transform infrared spectra and gel permeation chromatography analyses qualitatively showed the crosslinking between the isocyanate group in isocyanated PBMA and the carboxylic group in SAA. Two tan δ peaks were shown in the blend system of SAA and isocyanated PBMA containing low concentrations of TMI (from 0 to 5 wt %), and the span of the two peaks became shorter as the TMI concentration increased. For a high TMI concentration (7 wt %), only one tan δ peaks was observed. This result means the interfacial crosslinking between isocyanated PBMA and SAA occurred fully, and thus the miscibility between two polymers was significantly improved. As these results showed, the tensile strength of the blend film of isocyanated PBMA and SAA was higher than that of pure PBMA and SAA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 792–798, 2003