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Breast microcalcifications are an important primary radiological indicator of breast cancer. However, microcalcification classification and diagnosis may be still challenging for radiologists due to limitations of the standard 2D mammography technique, including spatial and contrast resolution. In this study, we propose an approach to improve the detection of microcalcifications in propagation-based phase-contrast X-ray computed tomography of breast tissues. Five fresh mastectomies containing microcalcifications were scanned at different X-ray energies and radiation doses using synchrotron radiation. Both bright-field (i.e. conventional phase-retrieved images) and dark-field images were extracted from the same data sets using different image processing methods. A quantitative analysis was performed in terms of visibility and contrast-to-noise ratio of microcalcifications. The results show that while the signal-to-noise and the contrast-to-noise ratios are lower, the visibility of the microcalcifications is more than two times higher in the dark-field images compared to the bright-field images. Dark-field images have also provided more accurate information about the size and shape of the microcalcifications.

The physical attributes of the zebrafish, including optical transparency during embryogenesis, large clutch sizes, external development, and rapid organogenesis were features that initially attracted developmental biologists to use this vertebrate as an experimental model system. With the progressive development of an extensive genetic "tool kit" and an ever-growing number of transgenic reporter lines, the zebrafish model has evolved into an informative system in which to mimic and study aspects of human disease, including those associated with bacterial infections. This chapter provides detailed protocols for microinjection of bacterial strains into zebrafish larvae and subsequent experiments to investigate single-larva bacterial burdens, live imaging of specific neutrophil and macrophage bactericidal functions, and how these protocols may be applied to drug discovery approaches to uncover novel immunomodulatory drugs.

The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and provide confidence in the first implementation of a graphite calorimeter on a synchrotron medical beam line.The graphite calorimeter has a core which rises in temperature when irradiated by the beam. A collimated x-ray beam from the synchrotron with well-defined edges was used to partially irradiate the core. Two filtration sets were used, one corresponding to an average beam energy of about 80 keV, with dose rate about 50 Gy/s, and the second filtration set corresponding to average beam energy of 90 keV, with dose rate about 20 Gy/s. The temperature rise from this beam was measured by a calibrated thermistor embedded in the core which was then converted to absorbed dose to graphite by multiplying the rise in temperature by the specific heat capacity for graphite and the ratio of cross-sectional areas of the core and beam. Conversion of the measured absorbed dose to graphite to absorbed dose to water was achieved using Monte Carlo calculations with the EGSnrc code. The air kerma measurements from the free-air chamber were converted to absorbed dose to water using the AAPM TG-61 protocol.Absolute measurements of the IMBL dose rate were made using the graphite calorimeter and compared to measurements with the free-air chamber. The measurements were at three different depths in graphite and two different filtrations. The calorimetry measurements at depths in graphite show agreement within 1% with free-air chamber measurements, when converted to absorbed dose to water. The calorimetry at the surface and free-air chamber results show agreement of order 3% when converted to absorbed dose to water. The combined standard uncertainty is 3.9%.The good agreement of the graphite calorimeter and free-air chamber results indicates that both devices are performing as expected. Further investigations at higher dose rates than 50 Gy/s are planned. At higher dose rates, recombination effects for the free-air chamber are much higher and expected to lead to much larger uncertainties. Since the graphite calorimeter does not have problems associated with dose rate, it is an appropriate primary standard detector for the synchrotron IMBL x rays and is the more accurate dosimeter for the higher dose rates expected in radiotherapy applications.

Aims—To examine the effects of rapid weight loss on mood and performance among amateur boxers.Methods—Participants were 16 experienced amateur boxers. In stage 1, structured interviews were used to assess the type of strategies that boxers used to reduce weight and the value of performing at their desired weight in terms of performance. In stage 2, boxers completed a 4 × 2 minute (1 minute recovery) circuit training session. Boxers completed the circuit training session on three different occasions with a week between each. The first test was used to familiarise the boxers with the circuit training task; the second and third tasks were at their training weight and championship weight, respectively. Participants were given one week to reduce their body weight to their championship weight using their preferred weight making strategies; boxers reduced their body weight by an average of 5.16% of body weight.Results—Boxers typically lost weight by restricting fluid and food intake in the week leading to competition. Repeated measures multivariate analysis of variance results indicated that rapid weight loss among boxers was associated with poor performance, increased anger, fatigue, and tension, and reduced vigour.Conclusions—Strategies used to make weight by boxers are associated with poor performance and a negative mood profile.

There is an increasing demand for acute care services due in part to rising proportions of older people and increasing rates of chronic diseases. To reduce pressure and costs in the hospital system, community-based post-acute care discharge services for older people have evolved as one method of reducing length of stay in hospital and preventing readmissions. However, it is unclear whether they reduce overall episode cost or expenditure in the health system at a more general level. In this paper, we review the current evidence on the likely costs and benefits of these services and consider whether they are potentially cost-effective from a health services perspective, using the Australian Transition Care Programme as a case study. Evaluations of community-based post-acute services have demonstrated that they reduce length of stay, prevent some re-hospitalisations and defer nursing home placement. There is also evidence that they convey some additional health benefits to older people. An economic model was developed to identify the maximum potential benefits and the likely cost savings from reduced use of health services from earlier discharge from hospital, accelerated recovery, reduced likelihood of readmission to hospital and delayed entry into permanent institutional care for participants of the Transition Care Programme. Assuming the best case scenario, the Transition Care Programme is still unlikely to be cost saving to a healthcare system. Hence for this service to be justified, additional health benefits such as quality of life improvements need to be taken into account. If it can be demonstrated that this service also conveys additional quality of life improvements, community-based programmes such as Transition Care could be considered to be cost-effective when compared with other healthcare programmes.

The effects of orthodontic tooth movement on pulpal responses are of interest to the clinician. Alterations to pulpal physiology may result in altered responses to external stimuli. This pilot project tested a small group of orthodontic patients during the early stages of treatment. Heat, cold and electrical stimuli were applied prior to treatment, after the placement of fixed appliances and after one month of force application. A smaller group was tested after two months of force application. One month after force application there was a lack of response to electrical stimulation but there was continued response to thermal stimulation. The lack of response to electrical stimulation continued in the smaller group up to two months. The results suggest that the outcome of electric pulp testing during orthodontic treatment should be interpreted cautiously. Thermal testing will offer more reliable data.

Drug-specific monoclonal antibodies against phencyclidine (PCP) and (+)-methamphetamine [(+)-METH] should bind to these drugs to block their discriminative stimulus effects. To determine if mouse monoclonal antibodies against PCP and (+)-METH can block the discriminative stimulus effects of the drugs in pigeons. Pigeons were trained to discriminate among intramuscular injections of saline, 1 mg/kg PCP, and 2 mg/kg (+)-METH. After responding stabilized, cumulative dose–response curves were obtained for PCP and (+)-METH. Doses of an anti-PCP antibody at 620 mg/kg (anti-PCP mAb6B5) with a K D of 1.3 nM for PCP and no measurable affinity for (+)-METH and 1,000 mg/kg doses of anti-(+)-METH antibody (anti-METH mAb6H7) with a K D of 41 nM for (+)-METH and no measurable affinity for PCP were subsequently administered, first alone and later in combination after which the dose–response curves were redetermined. When the antibodies were given alone, the anti-PCP antibody blocked the discriminative stimulus effects of PCP, but not those of (+)-METH, and the anti-(+)-METH antibody blocked the discriminative stimulus effects of (+)-METH, but not those of PCP. The anti-PCP antibody shifted the PCP dose–response curve further to the right and for a longer time than the anti-(+)-METH antibody shifted the dose response curve for (+)-METH. When the anti-PCP and anti-(+)-METH antibodies were administered on the same day, the discriminative stimulus effects of both drugs were completely blocked 1 day after antibody administration. These experiments demonstrate the high specificity of the antibodies for the drugs to which they bind and show that monoclonal antibodies can be combined to antagonize the effects of more than one drug.

Recent tests of a gamma-ray imaging telescope, which incorporated a coded aperture mask and multiwire proportional counter system produced good images of a tritium target source which was used to generate the 20 MeV protons at a proton Van de Graaff accelerator. This paper indicates what performance might be expected if a large area drift chamber were used in conjunction with a coded aperture mask. The prospects for achieving significant scientific results if such a system were flown on a variety of space vehicles are discussed.

The effects of a 185-min exposure to 48 degrees C db/33 degrees C wb, onintravascular volume and osmolarity and on intravascular electrolyte, aldosterone, and cortisol concentrations have been studied in five male subjectsbefore and after acclimatization to heat. Changes in the hematocrit and plasma protein concentration indicated that a hemodilution occurred during thefirst 35 min of the heat exposures, and that this was followed by a hemoconcentration. Although these changes in intravascular volume were not affected by acclimatization, the plasma volume after heat acclimatization was 6.7%greater than before. This increase in plasma volume was associated with an elevation in the ratio [Na]/[K]. However, since plasma osmolarity decreasedthe intravascular expansion could not be explained in terms of elevated electrolyte levels. Plasma aldosterone and cortisol levels were not affected by heat acclimatization, although both were elevated following exercisein the heat. It is concluded that the adrenal cortex is not an important factor in maintaining a state of heat acclimatization once a salt balance hasbeen achieved.

Based on monoenergetic proton beam tests of both NaI and CsI, a method for estimating the spallation background, due to the cosmic ray protons and trapped protons, has been developed. Comparisons between the calculated background noise and those measured by telescopes on board satellites are made. Good agreements of these comparisons demonstrate that the approach is capable of providing realistic estimates for specific space borne gamma-ray telescopes in well defined orbits.

A long-term study of 13 active galaxies has been carried out at 10.7 GHz over the period September 1980 to April 1982. The sources were observed at approximately monthly intervals and most of them were selected because they are also X-ray sources. The data obtained are used to measure their respective variabilities and to search for any correlations with other source parameters. No obvious relationship to radio or X-ray luminosity was found, though there does appear to be two distinct levels of radio variability for these sources and clear evidence of higher X-ray than radio variability.

An array of 30 position-sensitive scintillator bars has been tested in a gamma-ray beam. The gamma-ray energies range from 6 MeV to 17 MeV. The bars are similar to those proposed for use in the GRASP gamma-ray telescope satellite imaging plane. They are manufactured from CsI(Tl) covered with a highly reflective diffusive wrapping, and are read out using large-area PIN photodiodes. Each bar measures 15.0 cm by 1.3 cm by 1.3 cm. The beam test unit comprised 30 bars stacked in a 5 by 6 array. The photodiodes were optically coupled to the end face of each bar and were connected to a processing chain consisting of a low-noise preamplifier, a high-gain shaping amplifier, and a digitization and data collection system. Several experiments were performed with the unit to assess the spectral response position resolution, and background-rejection capabilities of the complete detector. The precision of the lateral position for an interaction measurement of lower energy photons was typically 10 mm. The position of interaction in the plane perpendicular to the beam has been shown to be well defined by the position of the bar in which the interaction closest to the front of the detector occurred. The resolution of the energy deposit in the whole detector at 6.14 MeV is 5%. >

A gamma ray detector system, originally designed for the GRASP gamma ray telescope satellite, is being developed. It has the ability to determine the position of a single photon interaction in one plane to an accuracy of 15 mm, and with a precision of

A direct immunofluorescence (DIF) technique (Imagen) and two enzyme immunoassay (EIA) techniques (Chlamydiazyme and IDEIA) were compared for the detection of Chlamydia trachomatis in genital specimens from 502 attenders at a genitourinary medicine clinic. Eighty-two attenders were regarded as infected: 67 with positive results by at least two of the three techniques and 15 by virtue of elementary bodies detected in stored EIA buffer samples. With a positivity criterion of greater than or equal to 6 bodies Imagen was 76% sensitive for men and 61% sensitive for women. The sensitivity of Chlamydiazyme was 73% for men and 90% for women; comparative values for IDEIA were 80% and 71%, respectively. All three techniques were over 98% specific. Sampling order appeared to influence the sensitivity of IDEIA for specimens from men. All three techniques were less sensitive in the absence of cervicitis. The performances of the EIA techniques compared favourably with that of the more established technique of DIF.

SUMMARY The metabolism of [14C]testosterone in vitro by various areas of the human foetal brain has been studied and compared with that of adult brain. The predominant metabolites were 5α-dihydrotestosterone and 5α-androstane-3α,17β-diol, and also androstenedione, and all areas of the foetal brain showed similar activity. In the foetal pituitary gland, the activity of 5α-reductase was less prominent than that of 17β-hydroxysteroid-dehydrogenase. Small quantities of oestradiol-17β were produced from testosterone by the hypothalamus, temporal lobe and amygdala only, and no aromatization could be detected in the pituitary gland. 5α-Reductase activity was much lower in adult brain tissues and no oestradiol was identified in adult temporal lobe tissue.