Doses under automatic exposure control (AEC) for direct digital radiographic (DDR) X-ray systems

Current guidelines quote tolerances for automatic exposure control (AEC) device performance for X-ray systems as 'Baseline ± X %'. However, in the situation where a baseline figure has not yet been achieved, as in the case of commissioning assessments, this tolerance is not relevant. The purpose of this work is to provide mean doses for direct digital radiography (DDR) X-ray system, operating in AEC, against which comparisons can be made. Dose measurements have been recorded under AEC operation on 29 DDR detectors from three different manufacturers. Two different testing protocols were examined: (1) water equivalent phantoms in front of the DDR detector and (2) aluminium block at the tube head. The average patient exit dose, using the aluminium block was 4.6 μGy with the antiscatter grid in place and 4.0 μGy with the grid removed. Using the water phantoms, the average dose was measured at 17.1 μGy with the antiscatter grid in place and 5.4 μGy with grid removed. Based on these results, it is clear that different testing configurations significantly impact on the measured dose.     

Predictive model to describe water migration in cellular solid foods during storage

BACKGROUND: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. RESULTS: Water migration in cellular solid foods involves migration through both the air cells and the solid matrix. For systems in which the water migration distance is large compared with the cell wall thickness of the solid matrix, the overall water flux through the system is dominated by the flux through the air. For these systems, water migration can be approximated well by a Fickian diffusion model. The effective diffusion coefficient can be expressed in terms of the material properties of the solid matrix (i.e. the density, sorption isotherm and diffusion coefficient of water in the solid matrix) and the morphological properties of the cellular structure (i.e. water vapour permeability and volume fraction of the solid matrix). The water vapour permeability is estimated from finite element method modelling using a simplified model for the cellular structure. CONCLUSION: It is shown that experimentally observed dynamical water profiles of bread rolls that differ in crust permeability are predicted well by the Fickian diffusion model. Copyright © 2011 Society of Chemical Industry     

Formation of cadaverine, histamine, putrescine and tyramine by bacteria isolated from meat, fermented sausages and cheeses

Enterobacteriaceae (EB, n = 149), Lactobacillus (LB, n = 162) and Leuconostoc sp. (LC, n = 89) and enterococci (EC, n = 137), isolated from raw meat (n = 65), fermented sausages (n = 50) and cheese (n = 55) samples, were cultivated in a broth containing precursor amino acids (each 3 g/l). After incubation, the liquid culture was chemically analysed for cadaverine (CAD), putrescine (PUT), histamine (HIS) and tyramine (TYR) formation at pH 5.2 and at pH 6.7. The majority of EB isolates (147 of 149) was capable of forming >100 mg/l of either CAD or PUT. Among the most frequently isolated species Hafnia alvei and Serratia liquefaciens, formation of >100 mg/l HIS occurred, but with low prevalence (1.6 and 6.5%, respectively). Twelve of 149 isolates (8%) were able to produce more than 10 mg/l HIS. One hundred forty-two isolates (95.3%) produced less than 10 mg/l TYR, and 7 isolates (4.7%) 10 mg/l to a maximum of 35.3 mg/l TYR. For LB + LC, one isolate (Leuconostoc mesenteroides ssp. mesenteroides) formed >100 mg/l PUT and one >100 mg/l CAD (of all 251 LB + LC isolates 0.4% each). Formation of >100 mg/l HIS and TYR was detected in 3.6 and 19% of the LB + LC isolates, respectively. For the EC isolates, maximum levels for PUT, CAD and HIS were 25.4 mg/l, 6.0 mg/l and 15.7 mg/l, respectively. TYR was formed in quantities of 100–1000 mg/l by 47.9% of EC faecalis (n = 75), and 59.7% of EC faecium (n = 62) isolates. More than 1000 mg/l TYR were formed by 50.7 and 35.5% of the isolates, respectively. A low initial pH of 5.2 compared to the initial pH of 6.7 favoured tyramine production by lactic acid bacteria, but was associated with lower CAD yield by EB. A considerable intra-species variability in amine formation was observed.     

Zur Elektrodenkinetik von Reinst – Eisen im Phosphatelektrolyten bei Feststoffeinschlag (Simulation von Erosionskorrosion)

Electrode kinetics of high purity iron in phosphate electrolytes under solid particle impact (Simulation of erosion corrosion) Erosion-corrosion of high purity iron was simulated by means of a vibration cell in a neutral phosphate electrolyte. The investigations were carried out to explain the initiation processes of this type of corrosion. The results confirm the general conception of the central role of reaction layer destruction in erosion-corrosion processes. Under these conditions a qualitative change in reaction layer formation occur. By solid impact the layers are destroyed locally and so conditions of pit nucleation exist. The destruction of the layers depends on the action of shear forces resulting from tensile or compressive strains.     

Proton conductivity in perovskite type yttrium doped barium hafnate

Yttria doped Ba-hafnates were prepared by solid state route and the proton conductivity of pressed samples of yttria doped barium hafnate was determined with impedance spectroscopy. The results are compared with existing data for cerates and zirconates. It was found that Ba-hafnates show a level of proton conduction that is comparable to that of doped Ba-zirconates at low and slightly higher at high temperatures. This is in agreement with the prediction based on the ionic radius of the tetravalent atom in the perovskite.     

ENIG的耐蚀性：一种改进的浸金工艺

为了了解ENIG化学变化对浸金耐蚀性的形响,探讨了浸金电镀溶液的pH值和化学性质与结果所得到的浸金层的耐蚀性之间的关系。     

Effects and generalizability of communally oriented HIV-AIDS prevention versus general health promotion groups for single, inner-city women in urban clinics.

A primary prevention, behavioral intervention designed to reduce HIV risk behavior was tested in a randomized, controlled trial with single, inner-city women. A total of 935 women were randomly assigned to 1 of 3 conditions: a small group, 6-session communally oriented HIV prevention intervention; a yoked general health promotion intervention control; or a standard care control. Both interventions involved the interactive use of videotapes by live group leaders. The HIV prevention intervention, in particular, resulted in significant positive effects on self-reported and behaviorally assessed safer-sex behavior. Women in the HIV prevention group showed reduced point prevalences of medically tested sexually transmitted diseases at follow-up in some comparisons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of DYSLEXPERT: A comparison of a knowledge-based system with experienced clinicians in the diagnosis of dyslexia

DYSLEXPERT is a knowledge-based system designed to support clinicians in the diagnosis of dyslexia. The system answers four questions that usually have to be addressed by human clinicians: Which areas of psychological functioning appear to be problematic? What tests would provide the relevant information? Are we actually dealing with dyslexia? How can the reading and spelling problems best be alleviated? In the present paper, we compare the competence of the program to the performance of four experienced diagnosticians on 20 cases of dyslexia and 20 cases of nondyslexia.The evaluation of the competence of DYSLEXPERT was based on three sets of data: the original case work, a reanalysis of the cases, and the results produced by DYSLEXPERT. The agreement between human and computer performance was measured using Cohen's kappa and Dice's measure of specific agreement. Statistical testing revealed the agreement between DYSLEXPERT and the reanalysis to be similar to the agreement between the original case work and the reanalysis.     

Conformational changes of Mal d 2, a thaumatin-like apple allergen,induced by food processing

Mal d 2, a thaumatin-like protein from apple was previously described to react to almost 75% of the apple allergic patient sera. Based on the molecular structure of this protein, the present study focused on the conformational stability of Mal d 2 in relation to in vitro IgE-binding under different physico-chemical conditions and proteolysis. The structural integrity of Mal d 2 was monitored using SDS–PAGE, Western blotting using polyclonal antibodies and human sera, fluorescence spectrometry and circular dichroism. Results confirmed the stability of Mal d 2. However, Mal d 2 was reactive to human serum IgEs mainly after reduction of disulphide bridges fixing the α-helical domain II. Contrary to previous assumptions, the current findings suggest that the allergenic epitopes of Mal d 2 are hidden inside the protein structure and none of the rigorous conditions applied in industrial juice processing or digestive proteolysis enhance or reduce the binding to IgE molecules.     

Safer sex knowledge, behavior, and attitudes of inner-city women.

Sexual behavior, knowledge of HIV transmission and prevention, perceived risk of AIDS, and safer sex behavior were studied in a sample of 289 single, pregnant, inner-city women. African-American and European-American women were equally represented. Women had poor AIDS knowledge. Sexual behavior placed women at risk for HIV infection due to the lack of condom or spermicide use. Women did not perceive themselves at risk for the AIDS virus, although they did recognize that heterosexuals were at risk. Their lack of risk perception was partly based on their having a single sexual partner. They did not regard their partner's current or past behavior as placing them at risk. Recommendations for intervention and cultural differences are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)