Evaluation of x-ray effective focal spot size dependency on x-ray exposure settings using edge response analysis

The effective focal spot size of x-ray tubes is one of the major factors that substantially affect the resultant x-ray images, and it is known to be dependent on the x-ray exposure setting used. This study aims to evaluate the relationship between the effective focal spot size and the tube current and voltage and assess its reproducibility among several x-ray tubes. The evaluation was performed using edge response analysis, in which a 1-mm thick tungsten edge was projected onto a flat panel detector with a magnification factor of 2. The edge image was then differentiated to obtain the line spread function, followed by a detector blur-removing process through Fourier analysis to obtain the true focus profile. The resultant focal spot size increased as the tube current increased, whereas it decreased as the tube voltage increased, as expected. The rate of change was similar along the width and the length directions, while the small focus changed more significantly than the large focus. The reproducibility among four x-ray tubes of the same model was excellent as the maximum variation < 20%. In conclusion, the edge response method can provide useful information on the x-ray focal spot relationship with the x-ray exposure settings used, as well as its reproducibility among several x-ray tubes.

Effects of nutrient limitation on cell growth, exopolysaccharide secretion and TEP production of Phaeocystis globosa

Phaeocystis globosa (P. globosa) often colonizes and produces mucus, which may cause massive blooms in coastal areas. To understand mechanism of the growth and the impact factors for better control of the bloom, we conducted a laboratory experiment on the effect of nitrogen (N) or phosphorus (P) limitation on the cell growth, production of exopolysaccharide (EPS), and transparent exopolymeric particles (TEP) of P. globosa. Results show no obvious differences in the N- and/or P-limitation in TEP production, polysaccharide secretion, and colony growth of P. globosa. Particularly in the death phase of the algae growth, the TEP production level in the experiment differed significantly, and was higher in the P-limitation group than that in the N-limitation group; additionally, the P-limitation group produced a relatively higher amount of EPS than N-limitation group, with greater cellular chlorophyll-a content, and in greater photosynthetic reaction rate of P. globosa cells, than those of the N-limitation group. However, under N-limited conditions, the algae colony survived longer. Under P-limited condition, P. globosa cells spend the photosynthesis-produced substances and energy for the secretion of extracellular substances but for cell reproduction, which was indicated by P. globosa cell growth and carbon content ratio between TEP and biomass.

Investigation of phenological, primary and secondary metabolites changes during flower developmental of Rosa damascena

Oil-bearing rose is a very valuable member of the Rosa genus. Despite the importance of oil-bearing rose, metabolic changes during flower development are not well understood. Thus, the objective of this study was to investigate the changes in phenological, primary and secondary metabolites and their interactions at five developmental stages of oil-bearing rose. Flower width, flower and petal fresh weights, petal area and petal relative water content increased from bud stage to blooming stage, while flower length and sepal area increased only at early stages. Thirty-seven essential oil components were identified at different stages of petal development and nonadecane, β-citronellol and n-heneicosane were the prevalent essential oil components regardless of stage. Sixteen fatty acids were identified and the amount of saturated fatty acids was higher than the mono and polyunsaturated fatty acids in all developmental stages. Eight organic acids were detected in petals and four of them (tartaric, malic, citric and succinic acids) showed significant changes, and total organic acids content decreased during flower development. Catechin and epicatechin were the most abundant phenolic compounds in petals. While total phenolic, flavonoid and free amino acids contents decreased during flower development, total free fatty acids content increased, but was not significant between the developmental stages. Correlation analysis between phenological traits and some metablolites revealed 20 significant correlations and 11 of which were positive. Results showed that flower development stages had significant effects on metabolite content and quality of products obtained, and significant shifts in metabolite type and content occurred at flower development stages III and IV.

An indicator of freeze-kill damages to fruit trees during flowering

This paper demonstrates the use of climatological data and published information to develop a thaw-freeze/freeze-kill indicator for fruit trees during flowering. In fruit-producing regions, when budding and flowering occur before the last spring freeze, a freeze-kill event can cause substantial losses. As spring onset is occurring earlier with climate change, thaw-freeze events have the potential to become more of a hazard both in terms of current production and in terms of potential adaptation strategies. To model the spring thaw-freeze and its magnitude or intensity, we proposed an indicator based on the accumulation of daily minimum temperature between successive freezing dates and its maximum value over the spring. This indicator was tested on apple and peach production in southern Ontario, Canada, using data from eight climate stations in southern Ontario. The indicator showed promise in its utility in that its magnitude was greater when freezing occurred after blooming and it was demonstrated to be correlated to the estimated blooming dates of apple and peach fruits grown in southern Ontario. The annual series was shown to fit the generalized extreme value distribution thereby allowing the extreme risk to be modelled and the return period to be calculated. It was also shown that the reported thaw-freeze events that caused significant apple and peach losses had a return period on the order of 10 years.

[Color Doppler Sonography: Device Settings Determine the Quality of Diagnosis and the Occurrence of Artifacts]

Color Doppler Sonography: Device Settings Determine the Quality of Diagnosis and the Occurrence of Artifacts Abstract. The major goal of the ultrasound examination is to find the right diagnosis. The correct setting of the device parameters is crucial for a reliable diagnosis. The examiner's knowledge of possible artifacts is helpful in evaluating the ultrasound images. Artifacts are not only present in B-mode sonography, but also in color Doppler sonography. Terms such as blooming, aliasing and twinkling refer to classic artifacts in color Doppler sonography. The causes of these artifacts and the possibilities of influencing them by device technology are presented and discussed. Exemplary images document the most important artifacts in color Doppler sonography.

The impact of two oil spill events on the water quality along coastal area of Kenting National Park, southern Taiwan

In 2009, the container ship Colombo Queen and the oil tanker W-O BUDMO grounded off Jialeshui and Houwan, respectively, in southern Taiwan. Water quality was monitored at each site to evaluate the environmental impact caused by the resulting oil spills. The results show that the PAHs, turbidity, and other nutrients increased shortly after oil spill, however levels of these parameters eventually returned to baseline levels. On the other hand, DO saturation, pH and chl. a decreased initially, reached maxima after 10days, and returned to the baseline levels after 14days. The chl. a concentration, pH and DO saturation fluctuated in a similar pattern at both sites during the oil spills, likely driven by algal blooms. In this study, we documented a full environmental recovery at coastal areas before, during and after the oil spills.

Removing the effect of blooming from potential energy measurement by employing total internal reflection microscopy integrated with video microscopy

Total internal reflection microscopy (TIRM) measures the interactions between a colloidal particle and a flat surface in aqueous solution. Recently, TIRM has further integrated with video microscopy (VM) and enabled the simultaneous measurements of multi-particle colloid-surface interactions in the same ensemble. However, there still remain challenges about accurate image acquisition due to blooming. Blooming means the number of photons reaching the detector exceeds its maximum capacity, and the excess photons will either spill to adjacent pixels or not be counted, leading to an obstacle from precise determination of intensity. Our result shows that blooming gives rise to a deviation of the measured potential energy from the classical theory of Derjaguin, Landau, Verway, and Overbeek (DLVO). Therefore, a correction method was developed in this work to deduce the real intensity from the experimental measurement. The relationship between scattered light intensity and exposure time deviates from linearity when blooming occurs. A correction equation was developed to recover the real intensity, which was then confirmed by the accordance between the corresponding potential energy profiles and the DLVO theory. This correction method is suitable for VM systems of colloidal probes illuminated by scattered light, broadening the application of VM imaging to investigate colloidal interactions.

Characterization of the surface physico-chemistry of plasticized PVC used in blood bag and infusion tubing

Commercial infusion tubing and blood storage devices (tubing, blood and platelets bags) made of plasticized PVC were analyzed by spectroscopic, chromatographic and microscopic techniques in order to identify and quantify the additives added to the polymer (lubricants, thermal stabilizers, plasticizers) and to put into evidence their blooming onto the surface of the devices. For all the samples, deposits were observed on the surface but with different kinds of morphologies. Ethylene bis amide lubricant and metallic stearate stabilizers were implicated in the formation of these layers. In contact with aqueous media, these insoluble deposits were damaged, suggesting a possible particulate contamination of the infused solutions.

Influence of 21days of vacuum-aging on color, bloom development, and WBSF of beef semimembranosus

Changes of color, proportions of myoglobin forms, pH, Warner-Bratzler shear force (WBSF) of beef m. semimembranosus (SM) were examined during 21days of vacuum-aging. Significant changes in lightness, redness, yellowness, chroma, and hue angle (p≤0.05) of SM during aging were found. Proportions of myoglobin forms changed on the 7th day of aging. Aging decreased WBSF in general, but a significant decrease (p≤0.05) from 67.86N to 55.3N was observed after day 14 of aging. The color parameters (L*, a*, C, ΔE) and O2Mb in 21-day aged SM were stabilized faster during blooming. Beef SM that had faster stabilization of bright red color during blooming were more tender (correlation of O2Mb with WBSF r=-0.87; p≤0.001). This could be important information for the producers, since the best quality traits could be achieved after sufficient blooming and aging time.

Investigation on the hazing of a Brazilian contemporary painting

A whitish crystalline-like coating was observed on the surface of the painting "Incêndio", 1990, produced by Emmanuel Nassar and awarded at the 6th Biennial of Cuenca. This work belongs to the Contemporary Art Museum of the University of São Paulo (MAC-USP) and such coating modified the artwork characteristics, causing an unpleasant effect and compromising its exhibition. The choice of the proper conservation and restoration strategies involves the understanding of the degradation process, demanding the identification of the chemical compounds formed on the painting surface, as well as of the other components in the painting. The results here obtained from Raman and optical microscopies, FTIR-ATR, SEM-EDS and GC-MS, revealed that the efflorescence chemical composition is almost only palmitic acid, with minor contents of stearic acid and their methyl esters, and that the paints are composed by chrome yellow, amorphous carbon and toluidine red pigment; an aluminum silicate filler in the black paint applied on the aluminum ground was also detected. Hierarchical Cluster Analyses (HCA) of the Raman spectra also revealed that the concentration of the efflorescence minor components depends on the paint composition. It was suggested, therefore, that the degradation process resulted from segregation and migration of mainly palmitic acid from the dried paints. Restoration methodologies used in similar cases, as well as factors that contribute to this process, were discussed.

Effects on colour characteristics of buffalo meat during blooming, retail display and using vitamin C during refrigerated storage

Experiments were conducted to determine the effect of blooming, retail display and vitamin C on colour changes/improvement of buffalo meat. To evaluate the effect of blooming, top round cuts of buffalo were allowed to bloom for 60 min. As colour bloomed, a* value increased from 6.47 to 10.01 at 45 min; no further changes occurred. In another study, top round cuts were kept at ambient temperature (36 ± 2 °C) and evaluated for instrumental colour during display. The instrumental redness value (a*) and chroma significantly increased (P < 0.05) after 12 h of display. During storage at refrigerated temperature, treatments consisted of injecting muscle section with 5 % by weight of 0.5, 1 and 2 % vitamin C solutions and a non-injected control (0 %). Each part was evaluated for instrumental colour changes and sensory traits (colour and discoloration score) at 0, 3, 6 and 9th day of refrigerated storage. The a* value (redness) increased significantly in all vitamin C treated buffalo meat samples as compared to control stored at 4 °C. The chroma was significantly higher (P < 0.05) in treated meat as compared to control. Buffalo meat containing vitamin C maintained the desired red meat colour throughout the storage period. The buffalo muscle treated with 2 % vitamin C was more effective in preventing discoloration than treated with 0.5 and 1 % vitamin C. In our study it is evident that as colour bloomed, a* value (redness) increased which indicated that buffalo muscles became redder immediately after exposure to air during blooming and retail display. Vitamin C at levels between 0.5 and 2 % will minimize the rapid discoloration that occurs at the muscle surface. However, 2 % concentration of vitamin C was more effective in minimizing the discoloration and improving colour stability.