Low-field MRI of laser polarized noble gas.

NMR images of laser polarized 3He gas were obtained at 21 G using a simple, homebuilt instrument. At such low fields magnetic resonance imaging (MRI) of thermally polarized samples (e.g., water) is not practical. Low-field noble gas MRI has novel scientific, engineering, and medical applications. Examples include portable systems for diagnosis of lung disease, as well as imaging of voids in porous media and within metallic systems.     

Matching exact results and one-instanton predictions in supersymmetric SU(N) theories

A one-instanton level test is performed for the proposed reparameterisation scheme matching the conjectured exact low energy results and instanton predictions for supersymmetric SU(N) gauge theories with 2N massless fundamental matter hypermultiplets across the entire quantum moduli space. The constants within the scheme which ensure agreement between the exact results and the instanton predictions for general N are derived. This constitutes a non-trivial test of the scheme, which eliminates the discrepancies arising when the two sets of results are compared.     

The neuroblast and angioblast chemotaxic factor SDF-1 (CXCL12) expression is briefly up regulated by reactive astrocytes in brain following neonatal hypoxic-ischemic injury

Background  

Stromal cell-derived factor 1 (SDF-1 or CXCL12) is chemotaxic for CXCR4 expressing bone marrow-derived cells. It functions in brain embryonic development and in response to ischemic injury in helping guide neuroblast migration and vasculogenesis. In experimental adult stroke models SDF-1 is expressed perivascularly in the injured region up to 30 days after the injury, suggesting it could be a therapeutic target for tissue repair strategies. We hypothesized that SDF-1 would be expressed in similar temporal and spatial patterns following hypoxic-ischemic (HI) injury in neonatal brain.     

Internal energy content of n-butylbenzene, bromobenzene, iodobenzene and aniline molecular ions generated by two-photon ionization at 266 nm. A photodissociation study

A technique to investigate photodissociation kinetics on a nanosecond time scale has been devised for molecular ions generated by multiphoton ionization (MPI) using mass-analyzed ion kinetic energy spectrometry. The branching ratio or rate constant has been determined for the photodissociation of the n-butylbenzene, bromobenzene, iodobenzene, and aniline molecular ions generated by MPI at 266 nm. The ion internal energies have been estimated by comparing the measured kinetic data with the previous energy dependence data. The analysis has shown that only those molecular ions generated by two-photon ionization contribute to the photodissociation signals. Around half of the available energy has been found to remain as molecular ion internal energy in the two-photon ionization process. Copyright 1999 John Wiley & Sons, Ltd.     

Ultrasonic vehicle guidance transducer

A vehicle guidance system has been developed using ultrasonic sensing. The ultrasonic technology is presented in this paper with reference to how it links in with the complete system. The ultrasonic unit is based on electrostatic transducer technology and comprises a separate linear array and curved divergent transmitter which gives it an effective field of view of 60° and a range of more than 5 m. The unit has been designed primarily for use on an unmanned vehicle travelling over rough, unknown terrain.     

Dehalogenation of α -haloketones and vic-dibromides with nickel boride

α-Haloketones and $\text{vic}$-dibromides are converted to the corresponding ketones and alkenes respectively with nickel boride generated $\text{in situ}$ from sodium borohydride and nickel chloride.     

Improved FIB milling process for TEM preparation of NiAlPt bulk alloy samples containing residual stress

NiAlPt alloys which undergo complex martensitic and twinning transformations during thermal cycling were prepared for Transmission Electron Microscopy (TEM) analysis using the Focused Ion Beam (FIB) milling process. Coupons of alloys that underwent cyclic heating, with no prior isothermal heat treatment contained a build-up of residual stress that caused sections of the foil to crack or buckle during the thinning process, rendering them useless. The solution was to mill strain isolation trenches perpendicular to the area of interest. These trenches acted as reservoirs for the released residual stress. This step was conducted in conjunction with reducing the beam current much earlier in the thinning process, thus ensuring minimum damage to the section being thinned. These two modifications of the standard FIB milling process, with emphasis on the strain isolation trenches, allowed for successful preparation of TEM samples from a bulk alloy containing residual stress.