DIMETHYL SULPHIDE FORMATION IN MALT—EFFECT OF MALTING CONDITIONS

The dimethyl sulphide (DMS) content of kilned malt, and, presumably, the level of precursor in green malt, is significantly affected by malting conditions. Increasing proteolysis favours increased DMS formation in the malt, particularly when induced by higher germination temperatures. The additives gibberellic acid and potassium bromate have opposing effects, some increase being caused by the former and significant reduction being achieved by the latter.     

THE APPLICATION OF SALT FORMATION IN THE CHEMISTRY AND TECHNOLOGY OF HOP RESINS

In natural product chemistry the satisfactory isolation of chemical compounds of scientific and/or commercial significance normally follows a pattern of fractionation which involves the utilization of a range of physical and chemical properties of the compounds present in the mixture. Vapour pressure and solubility are the physical properties traditionally made use of in the initial stages of fractionation. Chemical properties normally enable somewhat more specific fractionation to be achieved. One chemical property that is widely used is the ability of a large number of compounds to form salts. In the case of the hop resins it is this specific chemical property which has played the most significant role in their isolation, characterization and commercial utilization. The historical development of this aspect of hop chemistry has been reviewed.     

Automated Compositional Abstraction Refinement for Concurrent C Programs: A Two-Level Approach

The state space explosion problem in model checking remains the chief obstacle to the practical verification of real-world distributed systems. We attempt to address this problem in the context of verifying concurrent (message-passing) C programs against safety specifications. More specifically, we present a fully automated compositional framework which combines two orthogonal abstraction techniques (operating respectively on data and events) within a counterexample-guided abstraction refinement (CEGAR) scheme. In this way, our algorithm incrementally increases the granularity of the abstractions until the specification is either established or refuted. Our explicit use of compositionality delays the onset of state space explosion for as long as possible. To our knowledge, this is the first compositional use of CEGAR in the context of model checking concurrent C programs. We describe our approach in detail, and report on some very encouraging preliminary experimental results obtained with our tool MAGIC.     

Radio frequency identification (RFID) performance: the effect of tag orientation and package contents

The objective of this research was to determine the relationship between different product types and tag orientations on the readability of RFID tags on shipping containers in a palletload that is driven through a portal type reader. This research finds that the content of packages can dramatically reduce the read rate. Only 25% of the tags on shipping containers containing water‐filled bottles could be read. Rice‐filled jars had a higher read rate (80.6%). Even empty boxes did not have a 100% read rate. For the variables without appreciable package contents, only 74–79% of loads had all of their tags read. The orientation of the tag does make a difference, especially when coupled with a filled package between it and the reader antennae. Tags facing outwards, towards the reader antennae, had the highest likelihood of a successful read. When tags for the boxes of water‐filled bottles were all facing downwards, no tags were read. Supply chain managers need to understand these limitations of the technology and find ways to overcome them before RFID can be successfully implemented in supply chains. Copyright © 2005 John Wiley & Sons, Ltd.     

Extending the dynamic range of fibre length and fibre aspect ratios by automated image analysis

An automatic image analysis system has been developed, that is capable of scanning a large sample area (70 mm × 70 mm) using transmitted light microscopy. The analysis, based on transparent algorithms, successfully discriminates between overlapping and touching fibres, so that sample preparation time is minimized. The system utilizes overlapping image frames to reconstruct partial fibre images and impart unique fibre length information in the range micrometres to millimetres. The software has been made adaptable to enable the accurate measurement of fibre lengths for fibres that curve over many millimetres. Data are presented illustrating the accurate measurement of fibre lengths over a large range of fibre aspect ratios.     

Long-term (5 year) effects of transient (silent) ischaemia on left ventricular systolic function in stable angina. Clinical and radionuclide study

AIMS: (a) to assess short (1 year) and long-term (5 year) changes in left ventricular ejection fraction in patients with stable coronary disease with or without ECG evidence of transient ischaemia during daily life on routine therapy, and (b) to assess whether patients with recurrent transient ischaemic episodes have a particular propensity to gradual deterioration in left ventricular ejection fraction in the absence of infarction. METHODS AND RESULTS: One hundred and forty eight patients (127 males; mean age 59 years), part of a natural history cohort of 172 patients who had undergone exercise testing, 48 h ambulatory ST monitoring, and resting radionuclide ventriculography at baseline, and who had not suffered any intervening cardiac event, underwent repeat radionuclide ventriculography at 1 year follow-up on identical or very similar medications. Furthermore, 56 patients (50 males; mean age 65 years) of this cohort, who had ischaemia both on exercise testing and ambulatory monitoring at baseline (n=33), or no ischaemia on either test at baseline (n=23), and who had suffered no intervening event, underwent repeat exercise testing, ambulatory monitoring and radionuclide ventriculography at a mean of 61.8 months follow-up. In 38 of these 56 cases, long-term testing mirrored baseline testing in terms of presence or absence of ischaemia (both tests +, n=25; both tests -, n=13). At one year there was no change in left ventricular ejection fraction, either for the whole group (n=148; left ventricular ejection fraction 47=11.6% - 47.13+11.07%, P=ns) or for subgroups with (n=62; left ventricular ejection fraction 48+12.1%-48.5+10.5%, P=ns) and without (n=86; left ventricular ejection fraction 46.2+10.4%-46.2+11.3%, P=ns) evidence of transient ischaemia at baseline. At 61 months, there was a small fall in mean left ventricular ejection fraction for the total study group (n=56; left ventricular ejection fraction 45.8+9.3%-42.1+8.8%, P<0.05); however, this fall was not significant for those patients with both baseline and 5 year evidence of transient ischaemia (n=25; left ventricular ejection fraction 44.9+8.7%-41.3+7.5%, P=0.056). CONCLUSION: In medically treated stable coronary patients who do not suffer any intervening cardiac event, recurrent transient (silent) ischaemic episodes do not, in themselves, lead to gradual deterioration in left ventricular systolic function over a 1-5 year period.     

Book Reviews

Abstract

Book reviewed in this article:

Recent Works on the Theme of Technology and Place

The Land That Could Be: Environmentalism and Democracy in the Twenty-First Century William A. Shutkin     

On the Continuity of High Efficiency Modes in Linear RF Power Amplifiers

A novel formulation for the voltage waveforms in high efficiency linear power amplifiers is described. This formulation demonstrates that a constant optimum efficiency and output power can be obtained over a continuum of solutions by utilizing appropriate harmonic reactive impedance terminations. A specific example is confirmed experimentally. This new formulation has some important implications for the possibility of realizing broadband >10% high efficiency linear RF power amplifiers.     

Adaptive Neural Network for Nuclear Medicine Image Restoration

A novel adaptive neural network is proposed for image restoration using a nuclear medicine gamma camera based on the point spread function of measured system. The objective is to restore image degradation due to photon scattering and collimator photon penetration with the gamma camera and allow improved quantitative external measurements of radionuclides in-vivo. The specific clinical model proposed is the imaging of bremsstrahlung radiation using ³²P and ⁹⁰Y because of the enhanced image degradation effects of photon scattering, photon penetration and poor signal/noise ratio in measurements of this type with the gamma camera. This algorithm model avoids the common inverse problem associated with other image restoration filters such as the Wiener filter. The relative performance of the adaptive NN for image restoration is compared to a previously reported order statistic neural network hybrid (OSNNH) filter by these investigators, a traditional Weiner filter and a modified Hopfield neural network using simulated degraded images with different noise levels. Quantitative metrics such as the change of signal to noise ratio (SNR) are used to compare filter performance. The adaptive NN yields comparable results for image restoration with a slightly better performance for the images with higher noise level as often encountered in bremsstrahlung detection with the gamma camera. Experimental attenuation measurements were also performed in a water tank using two radionuclides, ³²P and ⁹⁰Y, typically used for antibody therapy. Similar values for an effective attenuation coefficient was observed for the restored images using the OSNNH filters and adaptive NN which demonstrate that the restoration filters preserves the total counts in the image as required for quantitative in-vivo measurements. The adaptive NN was computationally more efficient by a factor 4–6 compared to the OSNNH filter. The filter architecture, in turn, is also optimum for parallel processing or VLSI implementation as required for planar and particularly for tomographic mode of detection using the gamma camera. The proposed adaptive NN method should also prove to be useful for quantitative imaging of single photon emitters for other nuclear medicine tomographic imaging applications using positron emitters and direct X-ray photon detection.