Performance and the i860 microprocessor

The internal design of the i860 CPU, which exploits pipelining and parallelism more than previous microprocessors, is described. The i860 uses RISC concepts and memory-performance optimizations in several novel ways. Other innovations include simultaneous floating-point operations similar to digital signal processing, a two-instruction-per-clock mode, fast floating-point pipelines graphics instructions, and high-bandwidth registers and caches on-chip. These features make it one of the fastest single-chip processors available     

The skin, free radicals, and oxidative stress

Oxidative stress involves the adverse effects of oxygen and other free radicals on living tissue. An overview of the various types of free radicals generated in the body, the basic chemistry of free radicals, and how they arise is presented. The importance of understanding the action of free radicals on specific target tissues in the skin and how this affects the physiology of the skin in relation to treatment is covered.     

Fully automatic segmentation of the brain in MRI

A robust fully automatic method for segmenting the brain from head magnetic resonance (MR) images has been developed, which works even in the presence of radio frequency (RF) inhomogeneities. It has been successful in segmenting the brain in every slice from head images acquired from several different MRI scanners, using different-resolution images and different echo sequences. The method uses an integrated approach which employs image processing techniques based on anisotropic filters and “snakes” contouring techniques, and a priori knowledge, which is used to remove the eyes, which are tricky to remove based on image intensity alone. It is a multistage process, involving first removal of the background noise leaving a head mask, then finding a rough outline of the brain, then refinement of the rough brain outline to a final mask. The paper describes the main features of the method, and gives results for some brain studies     

Using human and model performance to compare MRI reconstructions

Magnetic resonance imaging (MRI) reconstruction techniques are often validated with signal-to-noise ratio (SNR), contrast-to-noise ratio, and mean-to-standard-deviation ratio measured on example images. We present human and model observers as a novel approach to evaluating reconstructions for low-SNR magnetic resonance (MR) images. We measured human and channelized Hotelling observers in a two-alternative forced-choice signal-known-exactly detection task on synthetic MR images. We compared three reconstructions: magnitude, wavelet-based denoising, and phase-corrected real. Human observers performed approximately equally using all three reconstructions. The model observer showed very close agreement with the humans over the range of images. These results contradict previous predictions in the literature based on SNR. Thus, we propose that human observer studies are important for validating MRI reconstructions. The model's performance indicates that it may provide an alternative to human studies.     

Application of analytical solutions to simulate some mine inflow problems in underground coal mining

The paper considers the interaction of ground water flow characteristics, aquifer parameters and mining geometry in order to estimate mine water inflows. The ground water flow conditions include both steady and unsteady state flow in an infinite and finite aquifers to an imaginary pumping out well. Both linear and non-linear flow equations are discussed. The application of non-linear equations has indicated that with the use of appropriate terms in these equations both laminar as well as turbulent inflows can be simulated. Water inflow to underground dewatering tunnels are also discussed in terms of both laminar and turbulent flow. Mine water inflow to a mine discharging to multiple dewatering outlet is also included. The application of various techniques outlined enables a more realistic estimate of water inflow to be made which can be conductive to planning mine dewatering systems with reference to economics and safety.     

Effect of bark beetle infestation on secondary organic aerosol precursor emissions

Bark beetles are a potentially destructive force in forest ecosystems; however, it is not known how insect attacks affect the atmosphere. The emissions of volatile organic compounds (VOCs) were sampled i.) from bark beetle infested and healthy lodgepole pine (Pinus contorta var. latifolia) trees and ii.) from sites with and without active mountain pine beetle infestation. The emissions from the trunk and the canopy were collected via sorbent traps. After collection, the sorbent traps were extracted with hexane, and the extracts were separated and detected using gas chromatography/mass spectroscopy. Canister samples were also collected and analyzed by a multicolumn gas chromatographic system. The samples from bark beetle infested lodgepole pine trees suggest a 5- to 20-fold enhancement in total VOCs emissions. Furthermore, increases in the β-phellandrene emissions correlated with bark beetle infestation. A shift in the type and the quantity of VOC emissions can be used to identify bark beetle infestation but, more importantly, can lead to increases in secondary organic aerosol from these forests as potent SOA precursors are produced.     

Combined sleep deprivation/chlorimipramine therapy of endogenous depression (author's transl)

A sleep deprivation/chlorimipramine therapy was compared to chlorimipramine therapy in endogenous depression. In the sleep deprivation/chlorimipramine group a quick and long-lasting remission of depressive symptoms could be demonstrated. In the chlorimipramine group a marked prolonged onset of action was seen.     

Adverse reactions to radiopharmaceuticals

This review covers the side effects and adverse reactions to radiopharmaceuticals that were reported in the literature over the past 25 years. The information published prior to 1970 is sporadic, but due to the increased utilization of nuclear medicine procedures and the recognition that radiopharmaceuticals may have pharmacologic side effects, a registry has existed since 1971 to tabulate information on such effects. This survey is medical, rather than pharmaceutical in emphasis and so the adverse reactions are classified according to the target-organ systems involved rather than according to the specific radionuclides or to pharmaceuticals. If any of the radiopharmaceuticals of present or past use are not mentioned in this review, it is because no reports on their side effects were retrived by us. Hopefully, the organized registry system suggested by the Society of Nuclear Medicine (SNM) will enable a more complete recording of side effects from radiopharmaceuticals in the future.     

The effects of drugs and anaesthetic agents on the urinary bladder and sphincters

The influence of sedative, anaesthetic and neuromuscular blocking drugs on diagnostic urethral pressure profiles and cystometrograms has been investigated. These agents have marked effects on the results obtained; in particular, the urethral pressure profile was raised by opiates and lowered by anaesthetic induction agents. Bladder capacity as measured by the cystometrogram was greatly increased by halothane. These findings indicate that urodynamic studies should be performed only on conscious unsedated patients.