Dose-reducing strategies in combination offers substantial potential benefits to females requiring X-ray examination

This work, using an adult anthropomorphic phantom, aimed to establish an optimised technique for ladies of child-bearing age undergoing antero-posterior (AP) pelvis and AP and lateral lumbar spine examinations. Phase one of the work involved introducing the following dose-reducing measures individually: increased kVp, increased focus-film distances, a carbon fibre cassette, a faster film/screen combination. The second phase established an optimised technique based on a combination of the parameters listed above. Radiation dose was measured using thermoluminescent dosimeters and image quality was evaluated using anatomical criteria. All dose-reducing methods were compared with a standard technique, currently being used in a Dublin hospital. The results demonstrated that the optimised procedure reduced effective dose by 77, 62 and 66% for AP pelvis and AP and lateral lumbar spine respectively (p < 0.05) compared with the standard technique, with no significant changes in image quality. Dose-reducing measures used in combination offer substantial potential for optimisation of radiological procedures.     

Rapid Annealing Response of the Hardened 1802 Bulk CMOS Microprocessor

Rapid annealing test results show that the hardened RCA/Sandia 1802 Bulk CMOS Microprocessor will function immediately after application of intense ionizing radiation pulses. This result was established in LINAC tests using a comprehensive test procedure which exercised the ?P in logarithmic time intervals from 10 ?s to 1000 s. It was found that no loss of functionality occurs for doses up to about 280 KRads. At 790 KRads, the device initially loses functionality but anneals in 600 ms. At 1.6 MRads, the device loses functionality for 4 s, and at 2.4 MRads, the device loses functionality for at least 1000 s. A sample size of five devices was used. The 1802 ?P was tested using hardware and software especially designed for this purpose. The microprocessor was exercised using software routines of exponentially increasing length starting at 10 ?s after the pulse. A measure of ?P functionality was therefore provided at logarithmically increasing sample times, After 2 seconds was reached, the routines repeated every two seconds up to 1000 seconds when the test ended. The hardware and software are described in detail.     

A novel method for the reduction of numbers of Listeria monocytogenes cells by freezing in combination with an essential oil in bacteriological media

The use of multiple freeze (-20 degrees C)-thaw cycles in combination with isoeugenol and polysorbate 80 was investigated as a method for the reduction of numbers of Listeria monocytogenes cells in a bacteriological medium. Three freeze (1 h, -20 degrees C)-thaw cycles in the presence of isoeugenol at concentrations of 0, 100, and 300 ppm resulted in average L. monocytogenes reductions of 0.69, 2.65, and 3.3 log10 MPN (most probable number) per ml, respectively. Increasing the number of freeze-thaw cycles further decreased cell numbers, with reductions of nearly 5 log10 MPN/ml being obtained with six freeze-thaw cycles. Freeze-thaw cycles were effective in reducing cell numbers at isoeugenol concentrations down to 25 ppm. Rapid freezing rates with liquid nitrogen were found to be less effective in reducing numbers of L. monocytogenes cells. Two rapid freeze-thaw cycles in the presence of 100 ppm isoeugenol and polysorbate 80 resulted in a reduction of 1.45 log10 MPN/ml. Two freezing (-20 degrees C) cycles involving slow freezing and thawing rates with samples being held frozen for 6 h for each cycle resulted in reductions larger than those obtained with faster freezing rates. It was found that complete thawing in freeze-thaw cycles was not necessary to achieve bactericidal action. The application of multiple freeze-thaw cycles in combination with low concentrations of isoeugenol could effectively reduce numbers of L. monocytogenes cells in bacteriological media.     

Signal extraction and optical design for an advanced gravitational-wave interferometer

We present an experimental demonstration of a locking and control scheme for an interferometer using a power-recycled resonant sideband extraction configuration and show that the measured response to mirror vibrations matches an optical model. We discuss some aspects of resonant sideband extraction that are relevant to gravitational-wave detection.     

Analysis of underivatized amino acids and their D/L-enantiomers by sheathless capillary electrophoresis/electrospray ionization mass spectrometry

Capillary electrophoresis/electrospray ionization-mass spectrometry (CE/ESI-MS) was applied to the analysis of underivatized amino acids and the separation of their D/L-enantiomers. Under full-scan mode, all standard protein amino acids were separated and detected at low-femtomole levels using a 130-cm-long, 20-microm-i.d., 150-microm-o.d. underivatized fused-silica capillary with 1 M formic acid as the background electrolyte. The CE/ESI-MS technique was also applied to the separation of L-arginine from L-canavanine (a close analogue of arginine where the terminal methylene linked to the guanidine group of arginine is replaced by an oxygen atom) in a complex mixture containing all standard protein amino acids. The utility of CE/ESI-MS in the analysis of real-world samples was demonstrated by the identification of two metabolic diseases (PKU and tyrosinemia) through blood analysis with minimal sample preparation. In addition, the on-line separation of 11 underivatized L-amino acids from their D-enantiomers was achieved by using a 30 mM solution of (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid as the background electrolyte.     

CE/electrospray ionization-MS analysis of underivatized d/l-amino acids and several small neurotransmitters at attomole levels through the use of 18-crown-6-tetracarboxylic acid as a complexation reagent/background electrolyte

A new capillary electrophoresis/mass spectrometry technique is introduced for attomole detection of primary amines (including several neurotransmitters), amino acids, and their d/l enantiomers in one run through the use of a complexation reagent while using only approximately 1 nL of sample. The technique uses underivatized amino acids in conjunction with an underivatized capillary, which significantly reduces cost and analysis time. It was found that when (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TCA, MW 440) was used as the background electrolyte/complexation reagent during the capillary electrophoresis/electrospray ionization-mass spectrometry (CE/ESI-MS) analysis of underivatized amino acids, stable complexes were formed between the amino acids and the 18-C-6-TCA molecules. These complexes, which exhibited high ionization efficiencies, were detectable at attomole levels for most amino acids. The detection limits of the AA/18-C-6-TCA complexes were on the average more than 2 orders of magnitude lower than that of the free amino acids in solution. In addition to lower detection limits under CE/ESI-MS, a solution of 18-C-6-TCA in the concentration range of 5-30 mM provided high separation efficiency for mixtures of l-amino acids as well as mixtures of d/l-amino acids. By using a solution of 18-C-6-TCA as the background electrolyte in conjunction with an underivatized, 130-cm-long, 20-microm-i.d., 150-microm-o.d. fused-silica capillary and by monitoring the m/z range of the amino acid/18-C-6-TCA complexes (m/z 515-700), most of the standard amino acids and many of their enantiomers were separated and detected with high separation efficiency and high sensitivity (nanomolar concentration detection limits) in one run. The solutions of 18-C-6-TCA also worked well as the CE/ESI-MS BGE for low-level detection of several neurotransmitters and some of their d/l enantiomers as well as for the analysis of amino acids at endogenous levels in lysed red blood cells.     

Evolving controllers for a homogeneous system of physical robots: structured cooperation with minimal sensors

We report on recent work in which we employed artificial evolution to design neural network controllers for small, homogeneous teams of mobile autonomous robots. The robots were evolved to perform a formation-movement task from random starting positions, equipped only with infrared sensors. The dual constraints of homogeneity and minimal sensors make this a non-trivial task. We describe the behaviour of a successful system in which robots adopt and maintain functionally distinct roles in order to achieve the task. We believe this to be the first example of the use of artificial evolution to design coordinated, cooperative behaviour for real robots.     

The management of arsenic wastes: problems and prospects

Arsenic has found widespread use in agriculture and industry to control a variety of insect and fungicidal pests. Most of these uses have been discontinued, but residues from such activities, together with the ongoing generation of arsenic wastes from the smelting of various ores, have left a legacy of a large number of arsenic-contaminated sites. The treatment and/or removal of arsenic is hindered by the fact that arsenic has a variety of valence states. Arsenic is most effectively removed or stabilized when it is present in the pentavalent arsenate form. For the removal of arsenic from wastewater, coagulation, normally using iron, is the preferred option. The solidification/stabilization of arsenic is not such a clear-cut process. Factors such as the waste's interaction with the additives (e.g. iron or lime), as well as any effect on the cement matrix, all impact on the efficacy of the fixation. Currently, differentiation between available solidification/stabilization processes is speculative, partly due to the large number of differing leaching tests that have been utilized. Differences in the leaching fluid, liquid-to-solid ratio, and agitation time and method all impact significantly on the arsenic leachate concentrations.This paper reviews options available for dealing with arsenic wastes, both solid and aqueous through an investigation of the methods available for the removal of arsenic from wastewater as well as possible solidification/stabilization options for a variety of waste streams.     

Antipatterns in the Creation of Intelligent Systems

A design pattern is a named problem-solution pair that enables large-scale reuse of software architectures or their components. Ideally, patterns explicitly capture expert knowledge, design trade-offs, and design rationale and make these lessons learned widely available for off-the-shelf use. They can also enhance developers' vocabulary - for example, by easing the transition to object-oriented programming. Conventionally, patterns consist of four elements: a name, the problem to be solved, the solution to the problem (often termed the refactored solution), and the consequences of the solution. Numerous sets of patterns (collectively known as pattern languages) exist for software design, analysis, management, and so on. Shortly after the notion of design patterns emerged, practitioners began discussing problem-solution pairs in which the solution did more harm than good. These have come to be known as antipatterns, and they are well known in the design and management communities     

从CES 2007看未来电视的发展趋势

CES(国际消费电子展)展会于1967年首次举办,当时的参展公司只有110家,参观人数有17500人。经过40年的岁月洗礼,CES已成为大型的电子展览盛会,引领了电子产业的最新趋势。