Scaling planar silicon devices

The generation-over-generation scaling of critical CMOS technology parameters is ultimately bound by nonscalable limitations, such as the thermal voltage and the elementary electronic charge. Sustained improvement in performance and density has required the introduction of new device structures and materials. Partially depleted SOI, a most recent MOSFET innovation, has extended VLSI performance while introducing unique idiosyncrasies. Fully depleted SOI is one logical extension of this device design direction. Gate dielectric tunneling, device self-heating, and single-event upsets present developers of these next-generation devices with new challenges. Strained silicon and high-permittivity gate dielectric are examples of new materials that will enable CMOS developers to continue to deliver device performance enhancements in the sub-100 nm regime.     

The Role of the γ/ γeutectic and porosity on the tensile behavior of a single-crystal nickel-base superalloy

The microstructure of a single-crystal nickel-base superalloy, PWA 1480, has been varied by heat treatment and hot isostatic pressing in order to study the role of the γ/yγ′ eutectic and porosity on subsequent tensile behavior. The level of porosity was found not to affect any of the tensile properties, while the γ/γ′ eutectic strongly influenced ductility. Eliminating the γ/γ′ eutectic increased ductility which was attributed to the cleavage fracture of this constituent. It is proposed that such cleavage of the γ/γ′ eutectic is initiated by the stress created from impinging slip bands, promoting shear localization, and final fracture along {111} slip planes. The precise nature of this fracture process is discussed with emphasis on the role of the γ/′ micro-structure. The deformation structure of PWA 1480 was also studied, and while different in some respects from many other single-crystal superalloys, its fracture process appears to be similar. Formerly Graduate Student, Department of Metallurgical Engineering and Materials Science, Carnegie Mellon University.     

ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb

OBJECTIVE: The purpose of this study was to evaluate ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb. CONCLUSION: Although rare, the diagnosis of ectopic drainage of the common bile duct into the duodenal bulb is important to prevent inadvertent damage during biliary tract or gastric surgery and to clarify the cause of chronic peptic ulcers.     

Coding region of NKX3.1, a prostate-specific homeobox gene on 8p21, is not mutated in human prostate cancers

Loss of heterozygosity at chromosome 8p21-22 is common in human prostate cancer, suggesting the presence of one or more tumor suppressor genes at this locus. A homeobox gene that is expressed specifically in adult human prostate, NKX3.1, the expression of which is regulated by androgen, maps to chromosome 8p21. Fine structure in situ mapping showed that NKX3.1 is proximal to MSR32 (macrophage scavenger receptor type II) and LPL (human lipoprotein lipase) and very close to NEFL (human neurofilament light chain) on 8p21. Single-strand conformational polymorphism analysis of 48 radical prostatectomy cancer specimens and 3 metastases for the entire coding region of NKX3.1 showed no tumor-specific sequence alterations in 50 specimens and total absence of the gene in 1 specimen known to have a biallelic deletion of 8p21. NKX3.1 was found to have a polymorphism at nucleotide 154 in codon 52 that resulted in a CGC-->TGC sequence change and an Arg-->Cys amino acid alteration (R52C). This polymorphism was present in 20% of DNA samples. If NKX3.1 is a target of the 8p21 LOH, it is not via disruption of the coding region of the gene.     

Memory beyond the hippocampus

Cultured hepatocytes of silver eel actively secreted only chylomicron-like lipoprotein. The rate of secretion per mg cellular protein per 24 hr was 2.2 times higher compared with that by yellow eel hepatocytes. Silver eel hepatocytes secreted lipids 2.5 times higher through the lipoprotein than yellow eel hepatocytes. Main lipid was triacylglycerol in either secreted lipoprotein and composition of apolipoproteins of both secreted lipoproteins was the same. The incorporation of 3H-leucine into the lipoprotein secreted by silver eel hepatocytes was 2.4 times higher, but that of 14C-acetate was not significantly different. Protein and lipids composition of plasma lipoproteins of silver eel was significantly higher and lower compared with those of yellow eel, respectively. We suggest that the secreted lipoprotein of silver eel hepatocytes transport much more lipids to other tissues than that of yellow eel hepatocytes.     

Dependence on the motif YIPP for the physical association of Jak2 kinase with the intracellular carboxyl tail of the angiotensin II AT1 receptor

Angiotensin II is the effector molecule of the renin-angiotensin system. Virtually all of its biochemical actions are mediated through a single class of cell-surface receptors called AT1. These receptors contain the structural features of the seven-transmembrane, G-protein-coupled receptor superfamily. Angiotensin II, acting through the AT1 receptor, also stimulates the Jak/STAT pathway by inducing ligand-dependent Jak2 tyrosine phosphorylation and activation. Here, we show that a glutathione S-transferase fusion protein containing the carboxyl-terminal 54 amino acids of the rat AT1A receptor physically binds to Jak2 in an angiotensin II-dependent manner. Deletional analysis, using both in vitro protocols and cell transfection analysis, showed that this association is dependent on the AT1A receptor motif YIPP (amino acids 319-322). The wild-type AT1A receptor can induce Jak2 tyrosine phosphorylation. In contrast, an AT1A receptor lacking the YIPP motif is unable to induce ligand-dependent phosphorylation of Jak2. Competition experiments with synthetic peptides suggest that each of the YIPP amino acids, including tyrosine 319, is important in Jak2 binding to the AT1A receptor. The binding of the AT1A receptor to the intracellular tyrosine kinase Jak2 supports the concept that the seven-transmembrane superfamily of receptors can physically associate with enzymatically active intracellular proteins, creating a signaling complex mechanistically similar to that observed with growth factor and cytokine receptors.