Family M42 aminopeptidase from the syntrophic bacterium Symbiobacterium thermophilum: characterization using recombinant protein

The chromosomal DNA of the syntrophic thermophile Symbiobacterium thermophilum contains open reading frames of the genes encoding family M42 aminopeptidases, Pep1079, Pep1080, and Pep1081. To characterize these peptidases, the genes were cloned into Escherichia coli and overexpressed. Our experiments using the recombinant proteins confirmed that Pep1079, Pep1080, and Pep1081 are components of arginyl or lysinyl aminopeptidases that require Co2+ for enzymatic activity. Coexistence of Pep1079 and Pep1080 is necessary for expressing high peptidase activity. Pep1081 enhances the activity of Pep1079 and Pep1080.     

Characterization of silicon dioxide films on a 4H-SiC Si(0001) face by fourier transform infrared (FT-IR) spectroscopy and cathodoluminescence spectroscopy

We used Fourier transform infrared (FT-IR) spectroscopy to characterize silicon dioxide (SiO(2)) films on a 4H-SiC(0001) Si face. We found that the peak frequency of the transverse optical (TO) phonon in SiO(2) films grown on a 4H-SiC substrate agrees well with that in SiO(2) films grown on a Si substrate, whereas the peak frequency of the longitudinal optical (LO) phonon in SiO(2) films on a 4H-SiC substrate is red-shifted by approximately 50 cm(-1) relative to that in SiO(2) films on a Si substrate. We concluded that this red-shift of the LO phonon is mainly caused by a change in inhomogeneity due to a decrease in density in the SiO(2) films. Furthermore, cathodoluminescence (CL) spectroscopy results indicated that the channel mobility of the SiC metal-oxide-semiconductor field-effect transistor (MOSFET) decreases roughly in proportion to the increase in the intensity of the CL peak at 460 and 490 nm, which is attributed to the increase in the number of oxygen vacancy centers (OVCs). FT-IR and CL spectroscopies provide us with a large amount of data on OVCs in the SiO(2) films on a 4H-SiC substrate.     

Effect of catch cup geometry on 3D boundary layer flow over the wafer surface in a spin coating

Recently, development of high technology has been required for the formation of thin uniform film in manufacturing processes of semiconductor as the semiconductor instruments become more sophisticated. Spin coating is usually used for spreading photoresist on a wafer surface. However, since rotating speed of the disk is very high in spin coating, the dropped photoresist scarers outward and reattaches on the film surface. A catch cup is set up outside the wafer in spin coating, and scattered photoresist mist is removed from the wafer edge by the exhaust flow generated at the gap between the wafer edge and the catch cup. In the dry process of a spin coating, it is a serious concern that the film thickness increases near the wafer edge in the case of low rotating speed. The purpose of this study is to make clear the effect of the catch cup geometry on the 3D boundary layer flow over the wafer surface and the drying rate of liquid film.     

Activity measurements of Al and Cu in Si–Al–Cu melt at 1273 and 1373 K by the equilibration with molten Pb

For the effective control of Al introduction to solidified Si during the solidification refining of Si with the Si–Al-based melt for the solar cell material or the LPE Si film growth processes from the Si–Cu–Al solvent, thermodynamic properties of the Si–Al–Cu melt were investigated at 1273 and 1373 K. Activities of Al and Cu in the Si–Al–Cu melt were measured by the equilibration with molten Pb. Also, the excess Gibbs energy of the melt was studied by the ternary regular solution model.

The evaluated thermodynamic properties of the Si–Al–Cu melt indicated that Cu addition to the Si–Al melt brings the smaller activity coefficient of Al and is effective for reducing the Al content of solidified Si from the melt more effectively than its dilution effect for Al.     

Evaluation of glomerular filtration rate by camera-based method in both children and adults

We describe a method to evaluate glomerular filtration rate (GFR) in both children and adults using 99mTc-diethylenetriamine pentaacetic acid (DTPA) and a gamma camera. METHODS: Renal scintigraphy with 99mTc-DTPA was performed in 40 children and 92 adults with various degrees of renal function. The percent renal uptake at 2-2.5 min after tracer arrival in the kidney was determined with background subtraction and correction for soft-tissue attenuation and was correlated by linear regression analysis with GFR measured from two blood samples. A perirenal region of interest was used for background subtraction. Renal depth was computed using the equations determined or validated on the basis of CT measurements, and the attenuation coefficient was set at 0.12. The obtained regression equation was used to predict GFR. Renal function was also assessed by the Gates' method. RESULTS: Percent renal uptake was closely correlated with GFR normalized for body surface area in all patients (y = 15.958x - 2.94; r = 0.939). GFR was successfully predicted using the regression equation in both children and adults. Gates' method severely overestimated GFR in children and provided less accurate values even in adults than our method. CONCLUSION: The method presented here requires neither blood sampling nor additional imaging and allows estimation of GFR in both children and adults.     

Neutrophil-endothelial cell interactions in gastrointestinal diseases

The adherence of neutrophils to the endothelium is a crucial early event in the inflammatory and immunological reaction. Neutrophil-endothelial cell interactions are known to be mediated by adhesion molecules that are expressed on each cell. Among the adhesion molecules expressed on leukocytes, the CD11/CD18 integrin family plays a major role in the adhesion and transendothelial migration of neutrophils. The two most extensively characterized endothelial cell adhesion molecules are intercellular adhesion molecule-1 and E-selectin. These adhesion molecules are involved in the pathogenesis of several digestive diseases such as Helicobacter pylori, non steroidal anti inflammatory drug- or stress-induced gastric mucosal injury, inflammatory bowel diseases.     

A 14-ns 14-Mb CMOS DRAM with 300-mW active power

A 4-Mb high-speed DRAM (HSDRAM) has been developed and fabricated by using 0.7-μm L_eff CMOS technology with PMOS arrays inside n-type wells and p-type substrate plate trench cells. The 13.18-mm×6.38-mm chip, organized as either 512 K word×8 b or 1 M word×4 b, achieves a nominal random-access time of 14 ns and a nominal column-access time of 7 ns, with a 3.6-V V_cc and provision of address multiplexing. The high level of performance is achieved by using a short-signal-path architecture with center bonding pads and a pulsed sensing scheme with a limited bit-line swing. A fast word-line boosting scheme and a two-stage word-line delay monitor provide fast word-line transition and detection. A new data output circuit, which interfaces a 3.6-V V_cc to a 5-V bus with an NMOS-only driver, also contributes to the fast access speed by means of a preconditioning scheme and boosting scheme. Limiting the bit-line voltage swing for bit-line sensing results in a low power dissipation of 300 mW for a 60-ns cycle time     

Transient global amnesia after general anesthesia

OBJECTIVE: To investigate the prevalence of coronary artery disease (CAD), atherothrombotic brain infarction (ABI), and peripheral arterial disease (PAD) in older Hispanics and the association with risk factors in this population. DESIGN: A retrospective analysis of charts from all Hispanics seen during January 1996 through July 1997 at an academic hospital-based geriatrics practice. SETTING: An academic, hospital-based, primary care geriatrics practice staffed by fellows in a geriatrics training program and by full-time faculty geriatricians. PATIENTS: One hundred sixty women and 53 men, mean age 80 +/- 8 years (range 64 to 100), were included in the study. MEASUREMENTS AND MAIN RESULTS: Of 213 Hispanics in the study, 59 (28%) had documented CAD, 43 (20%) had ABI, 34 (16%) had PAD, and 90 (42%) had either CAD, ABI, or PAD. Serum total cholesterol and triglycerides were measured in 202 of 213 subjects (95%). Serum high-density lipoprotein cholesterol was measured in 137 of 213 patients (64%). Other risk factor data were documented in all patients. Multiple logistic regression analysis performed in 202 patients using the variables age, gender, cigarette smoking, hypertension, diabetes mellitus, obesity, serum total cholesterol, and serum triglycerides showed statistically significant associations between prevalent CAD, ABI, or PAD and age (P = .002, odds ratio (OR) = 1.083), cigarette smoking (P = .002, (OR) = 3.865), hypertension (P = .007, (OR) = 2.749), diabetes mellitus (P = .028, (OR) = 2.386), obesity (P = .014, (OR) = 2.608), serum total cholesterol (P < 0.001, (OR) = 1.025), and serum triglycerides (P = .017, (OR) = .993). CONCLUSIONS: Either CAD, ABI, or PAD was present in 42% of 213 older Hispanics. There were statistically significant associations between prevalent CAD, ABI, or PAD in older Hispanics and risk factors, including age, cigarette smoking, hypertension, diabetes mellitus, obesity, and serum total cholesterol.