Pulsed electron-beam annealing of phosphorus-implanted silicon

Electrical properties of phosphorus-implanted silicon annealed by a single shot of a high-power pulsed electron beam have been studied by differential Hall-effect and sheet-resistivity measurements. Nearly 100% electrical activation of implanted phosphorus can be obtained after electron-beam annealing at an incident energy density of 0.92 J/cm2. Uniformly distributed carrier concentration profiles have been formed by electron-beam annealing.     

A 2.5-GFLOPS, 6.5 million polygons per second, four-way VLIWgeometry processor with SIMD instructions and a software bypassmechanism

A four-way very long instruction word (VLIW), 312-MHz geometry processor with peripheral component interconnect/accelerated graphic port bus bridge was implemented in a 0.21-μm, 2.5-V, three-layer-metal CMOS process. We adopted (1) a software bypass mechanism, (2) single-instruction multiple-data stream instructions, (3) four sets of floating-point multiply add and accumulate execution units, (4) special condition code registers and a branch condition generator for a clipping operation, and (5) automatic clock delay tuning methodology. As a result of these features, we achieved a performance of 2.5 GFLOPS and 6.5 million polygons per second for a three-dimensional geometry processor, which is the highest published performance as a single geometry processor. The processor is applicable to computer-aided-design systems that require very high graphics performance     

Lasing band-edge identification for a surface-emitting photonic crystal laser

The possibility of single-mode oscillation over a large cavity area for photonic crystal lasers emitting at the photonic band edge has resulted in much interest in such materials for new forms of solid-state laser. In this paper, we measure the photonic bandstructure in our sample and identify the lasing band edge. By mapping out the bandstructure at the /spl Gamma/-point, we have observed fine structure at the band edge. The experimental results are in good agreement with the theoretically predicted bandstructure. Above threshold, we observe a lasing peak at 965 nm at one of the band edges. The far-field distribution of the laser is measured, showing an annular profile and azimuthal polarization. Calculations on the far-field distribution at the lasing band edge suggest the annular profile is due to an anti-symmetric resonant mode.     

Long Preservation of AAV-Transduced Fluorescence by a Modified Organic Solvent-Based Clearing Method

The development of tissue clearing technologies allows 3D imaging of whole tissues and organs, especially in studies of the central nervous system innervated throughout the body. Although the three-dimensional imaging of solvent-cleared organs (3DISCO) method provides a powerful clearing capacity and high transparency, the rapid quenching of endogenous fluorescence and peroxide removal process decreases its practicability. This study provides a modified method named tDISCO to solve these limitations. The tDISCO protocol can preserve AAV-transduced endogenous EGFP fluorescence for months and achieve high transparency in a fast and simple clearing process. In addition to the brain, tDISCO was applied to other organs and even hard bone tissue. tDISCO also enabled us to visualize the long projection neurons and axons with high resolution. This method provides a fast and simple clearing protocol for 3D visualization of the AAV- transduced long projection neurons throughout the brain and spinal cord.     

Novel sensing system for glucose based on the complex formation between phenylborate and fluorescent diol compounds

From the standpoints of long-term stability and simple handling, a glucose sensor composed of totally synthetic sensing moieties should be of great advantage. This study was performed to demonstrate the feasibility of a novel glucose sensing system in an aqueous milieu based on a change in the fluorescence on competitive binding between a fluorescent diol compound and glucose toward a phenylborate compound. 6,7-Dihydroxy-4-methyl-coumarin (DHMC) was selected as a fluorophore, and 3-propionamidophenylboronic acid (PAPBA) as a phenylborate compound. The relationship between the glucose concentration and fluorescence intensity was linear in the range of 0 to 500 mg/dl of glucose. The availability of various derivatives of DHMC and phenylborate compounds allows the incorporation of these functionalities on the tip of an optical fiber to construct an opto-sensing system for glucose.     

Interaction of beta-lactam antibiotics with H+/peptide cotransporters in rat renal brush-border membranes

Two H+/peptide cotransporters, PEPT1 and PEPT2, are expressed in the kidney, mediating the renal tubular reabsorption of oligopeptides and beta-lactam antibiotics. We examined the interactions of beta-lactam antibiotics with peptide transporters in rat renal brush-border membranes by evaluating the inhibitory potencies of the antibiotics against glycylsarcosine transport. Western blot analysis revealed that PEPT1 and PEPT2 were expressed in the renal brush-border membranes with the apparent molecular masses of 75 and 105 kDa, respectively. Using renal brush-border membrane vesicles, the uphill transport of glycylsarcosine was observed in the presence of an inward H+ gradient and an inside-negative membrane potential. Two transport systems with high affinity (Km of 50 microM) and low affinity (Km of 1.2 mM) appeared kinetically to mediate the glycylsarcosine uptake. The inhibition constants of the antibiotics for glycylsarcosine transport were more closely correlated with those in stable LLC-PK1 cells transfected with rat PEPT2 rather than PEPT1 cDNA. The beta-lactam antibiotics with an alpha-amino group showed trans-stimulation effects on the glycylsarcosine uptake, suggesting that these antibiotics and glycylsarcosine share a common peptide transporter. However, the antibiotics lacking an alpha-amino group failed to show the trans-stimulation effect. It is concluded that amino-beta-lactam antibiotics at therapeutic concentrations interact predominantly with PEPT2 localized in the brush-border membranes of rat kidney.     

Preparation and surface active properties of alcohol ethoxylates with an amide oxime terminal group

Amide oxime compounds have become of major interest because they can complex with uranium, gallium and various transition metal ions. In this work surface active amide oximes were prepared to make some functions of the amide oxime group exhibit as molecular aggregates in aqueous media. Amide oximes were obtained from nitriles which were prepared by the cyanoethylation of alcohol ethoxylates with a monodispersed oligo(oxyethylene) group. Surface active properties of these compounds were measured under various conditions and were compared with nonionics of the alcohol ethoxylate type. The pKa₁ values of these amide oximes were about five, and they acted as cationic surfactants under acidic conditions and nonionic ones under neutral and basic conditions. When they served as nonionics, the cloud point, CMC, γ_CMC and foaming properties of surface active amide oximes were similar to other alcohol ethoxylate nonionics.