1,614 research outputs found
Characterization of the Soluble Nanoparticles Formed through Coulombic Interaction of Bovine Serum Albumin with Anionic Graft Copolymers at Low pH
A static light scattering (SLS) study of bovine serum albumin (BSA) mixtures
with two anionic graft copolymers of poly (sodium acrylate-co-sodium
2-acrylamido-2-methyl-1-propanesulphonate)-graft-poly (N,
N-dimethylacrylamide), with a high composition in poly (N,
N-dimethylacrylamide) (PDMAM) side chains, revealed the formation of oppositely
charged complexes, at pH lower than 4.9, the isoelectric point of BSA. The
core-corona nanoparticles formed at pH = 3.00, were characterized. Their
molecular weight and radius of gyration were determined by SLS, while their
hydrodynamic radius was determined by dynamic light scattering. Small angle
neutron scattering measurements were used to determine the radius of the
insoluble complexes, comprising the core of the particles. The values obtained
indicated that their size and aggregation number of the nanoparticles, were
smaller when the content of the graft copolymers in neutral PDMAM side chains
was higher. Such particles should be interesting drug delivery candidates, if
the gastrointestinal tract was to be used
The relation between sustainability performance and stock market returns: An Empirical analysis of the Dow Jones Sustainability Index Europe
This paper investigates the relation between corporate financial performance (CFP) and corporate sustainability performance (CSP). This is done by first analyzing a sample of European stocks that were added to or deleted from the Dow Jones Sustainability Europe Index (DJSI Europe) over the period 2009â2013, and second by analyzing a sample of European stocks that were recognized as industry group leaders in CSP by the DJSI Europe over the same period. The impacts are measured in terms of (abnormal) stock returns. For the first analysis no strong evidence could be found that the announcement of the inclusion and exclusion events has any significant impact on stock return. However, on the day of change (CD) and in the period following CD, index inclusion (exclusion) stocks experience a significant but temporary increase (decrease) in stock return. These results seem to support Harris and Eitanâs (1986) price pressure hypothesis, which postulates that event announcement does not carry information and any shift in demand and hence the corresponding price change is temporary. From the second analysis, on industry group leaders, it can be concluded that the market rewards firms with high CSP. In the period after the day of change, industry group leader stocks experience a permanent and significant positive growth in stock returns. This conclusion can be supported by the resource based perspective, which posits that firms capable of investing heavily in CSP have greater underlying resources which in turn should produce higher financial performance (Alexander and Bucholz, 1978; Waddock and Graves, 1997; Clarkson et al., 2006)
Reduced uptake of the proliferation-seeking radiotracer technetium-99m-labelled pentavalent dimercaptosuccinic acid in a 47-year-old woman with severe breast epithelial hyperplasia taking ibuprofen: a case report
<p>Abstract</p> <p>Introduction</p> <p>Recent studies have reported a risk reduction in the progression of benign breast disease to breast carcinoma through COX-2 pathways.</p> <p>Case presentation</p> <p>We present a case of severe epithelial hyperplasia in a 47-year-old woman with increased breast density submitted to scintimammography by the proliferation-imaging tracer Technetium-99m-labelled pentavalent dimercaptosuccinic acid, before and after an oral ibuprofen treatment for 4 weeks. The radiotracer uptake after ibuprofen intake was significantly reduced, both visually and by semi-quantitative analysis, based on a calculation of lesion-to-background ratios.</p> <p>Conclusion</p> <p>In proliferating breast lesions, scintigraphically displayed reduction in Technetium-99m-labelled pentavalent dimercaptosuccinic acid uptake may indicate inhibition by ibuprofen in the pathway of malignant epithelial cell transformation.</p
A Microcosm of Colour and Shine. The Polychromy of Chryselephantine Couches from Ancient Macedonia
The present work examines the polychromy applied to a number of fragmentary ivory small-scale sculptures that served as components of the luxurious decoration of chryselephantine couches from ancient Macedonia. The ivory fragments come from funerary contexts (the tomb of Philip II at Aigai, the Macedonian tomb II of Korinos at Pydna and the Macedonian tomb III of Aghios Athanassios near Thessaloniki), all of which are dated to the last quarter of the fourth century BC. The use of bright pigments on the laboriously executed faces of the figures and their garments, together with the gold leaf applied onto the hair and the background, conveys a powerful effect of polychromy that would have immediately caught the spectatorâs eye, enhancing the overall aesthetic and material value of such lavishly decorated furniture. The identification of the pigments and the techniques of their application have been studied with the use of analytical methods (XRF, micro-XRF, XRD and SEM-EDS) and multi spectral imaging (Visible Induced Luminescence).Le prĂ©sent article est consacrĂ© aux traces de polychromie retrouvĂ©es sur un certain nombre de sculptures fragmentaires en ivoire de petit format composant la somptueuse dĂ©coration des lits de banquets chrysĂ©lĂ©phantins de la MacĂ©doine antique. Ces fragments en ivoire ont Ă©tĂ© dĂ©couverts dans des sĂ©pultures (la tombe de Philippe II Ă Aigai, la tombe macĂ©donienne II de Korinos Ă Pydna et la tombe III dâAghios Athanassios prĂšs de Thessalonique, toutes datĂ©es du dernier quart du ive siĂšcle avant JĂ©sus-Christ.Lâutilisation de pigments Ă©clatants sur les visages soigneusement travaillĂ©s des figurines ainsi que sur leurs vĂȘtements, tout comme la feuille dâor, appliquĂ©e sur la chevelure et sur le fond, leur confĂšrent une puissance de chatoiement qui devait immĂ©diatement frapper le spectateur, renforçant lâimpression esthĂ©tique comme la valeur matĂ©rielle de ce mobilier si fastueusement dĂ©corĂ©.Lâidentification des pigments et les techniques de mise en Ćuvre employĂ©es ont Ă©tĂ© Ă©tudiĂ©es Ă lâaide dâanalyses en XRF, micro-XRF, DRX, MEB-EDS et de lâimagerie multi-spectrale (photoluminescence
The thermodynamic structure of summer Arctic stratocumulus and the dynamic coupling to the surface
The vertical structure of Arctic low-level clouds and Arctic boundary layer is studied, using observations from ASCOS (Arctic Summer Cloud Ocean Study), in the central Arctic, in late summer 2008. Two general types of cloud structures are examined: the "neutrally stratified" and "stably stratified" clouds. Neutrally stratified are mixed-phase clouds where radiative-cooling near cloud top produces turbulence that generates a cloud-driven mixed layer. When this layer mixes with the surface-generated turbulence, the cloud layer is coupled to the surface, whereas when such an interaction does not occur, it remains decoupled; the latter state is most frequently observed. The decoupled clouds are usually higher compared to the coupled; differences in thickness or cloud water properties between the two cases are however not found. The surface fluxes are also very similar for both states. The decoupled clouds exhibit a bimodal thermodynamic structure, depending on the depth of the sub-cloud mixed layer (SCML): clouds with shallower SCMLs are disconnected from the surface by weak inversions, whereas those that lay over a deeper SCML are associated with stronger inversions at the decoupling height. Neutrally stratified clouds generally precipitate; the evaporation/sublimation of precipitation often enhances the decoupling state. Finally, stably stratified clouds are usually lower, geometrically and optically thinner, non-precipitating liquid-water clouds, not containing enough liquid to drive efficient mixing through cloud-top cooling
Dual Energy Method for Breast Imaging: A Simulation Study
Dual energy methods can suppress the contrast between adipose and glandular tissues in the breast and therefore enhance the visibility of calcifications. In this study, a dual energy method based on analytical modeling was developed for the detection of minimum microcalcification thickness. To this aim, a modified radiographic X-ray unit was considered, in order to overcome the limited kVp range of mammographic units used in previous DE studies, combined with a high resolution CMOS sensor (pixel size of 22.5 m) for improved resolution. Various filter materials were examined based on their K-absorption edge. Hydroxyapatite (HAp) was used to simulate microcalcifications. The contrast to noise ratio (CNR ) of the subtracted images was calculated for both monoenergetic and polyenergetic X-ray beams. The optimum monoenergetic pair was 23/58 keV for the low and high energy, respectively, resulting in a minimum detectable microcalcification thickness of 100 m. In the polyenergetic X-ray study, the optimal spectral combination was 40/70 kVp filtered with 100 m cadmium and 1000 m copper, respectively. In this case, the minimum detectable microcalcification thickness was 150 m. The proposed dual energy method provides improved microcalcification detectability in breast imaging with mean glandular dose values within acceptable levels
Desperately seeking niches: Grassroots innovations and niche development in the community currency field
The sustainability transitions literature seeks to explain the conditions under which technological innovations can diffuse and disrupt existing socio-technical systems through the successful scaling up of experimental ânichesâ; but recent research on âgrassroots innovationsâ argues that civil society is a promising but under-researched site of innovation for sustainability, albeit one with very different characteristics to the market-based innovation normally considered in the literature. This paper aims to address that research gap by exploring the relevance of niche development theories in a civil society context. To do this, we examine a growing grassroots innovation â the international field of community currencies â which comprises a range of new socio-technical configurations of systems of exchange which have emerged from civil society over the last 30 years, intended to provide more environmentally and socially sustainable forms of money and finance. We draw on new empirical research from an international study of these initiatives comprising primary and secondary data and documentary sources, elite interviews and participant observation in the field. We describe the global diffusion of community currencies, and then conduct a niche analysis to evaluate the utility of niche theories for explaining the development of the community currency movement. We find that some niche-building processes identified in the existing literature are relevant in a grassroots context: the importance of building networks, managing expectations and the significance of external âlandscapeâ pressures, particularly at the level of national-type. However, our findings suggest that existing theories do not fully capture the complexity of this type of innovation: we find a diverse field addressing a range of societal systems (money, welfare, education, health, consumerism), and showing increasing fragmentation (as opposed to consolidation and standardisation); furthermore, there is little evidence of formalised learning taking place but this has not hampered movement growth. We conclude that grassroots innovations develop and diffuse in quite different ways to conventional innovations, and that niche theories require adaptation to the civil society context
Relationship of cell proliferation (Ki-67) to (99m)Tc-(V)DMSA uptake in breast cancer
INTRODUCTION: The aim of the present study was to identify the relationships between the uptake of radiotracers â namely pentavalent dimercaptosuccinic acid [(V)DMSA] and sestamibi (MIBI) â and the following parameters in primary breast cancer: steroid receptor concentrations (i.e. estrogen receptor [ER] and progesterone receptor [PR]), Ki-67 expression, tumor size, tumor grade, age, and levels of expression of p53 and c-erbB-2. In addition, by multivariate regression analysis, we further isolated those factors with independent associations with (V)DMSA and/or MIBI uptake in primary breast cancer. METHODS: Thirty-four patients with histologically confirmed breast carcinoma underwent preoperative scintimammography with technetium-99m ((99m)Tc)-(V)DMSA and/or (99m)Tc-MIBI in consecutive sessions 10 and 60 min after administration of 925â1110 MBq of each radiotracer. The tumor-to-background ratio was calculated and correlated with the presence of ER, PR, Ki-67, tumor size, tumor grade, p53, and c-erbB-2. ER, PR, p53, and c-erbB-2 were determined immunohistochemically. The analysis included tumor-to-background ratio of (V)DMSA and MIBI uptake as dependent and all of the other parameters as independent variables. RESULTS: Correlation was positive between Ki-67 and (V)DMSA (r = 0.37 at 10 min, P = 0.038; r = 0.42 at 60 min, P = 0.018) and inverse between PR and (V)DMSA uptake (r = -0.46 at 10 min, P = 0.010; r = -0.51 at 60 min, P = 0.003). Multivariate regression analysis demonstrated a positive correlation between Ki-67 and (V)DMSA at 60 min (P = 0.045). Ki-67 was not significantly correlated with MIBI uptake, whereas tumor size was positively correlated with MIBI uptake at 60 min both in univariate (r = 0.45, P = 0.027) and multivariate analysis (P = 0.024). Negative correlations were observed between (V)DMSA uptake and ER, as well as between ER/PR and MIBI uptake, but these were not significant. CONCLUSION: Ki-67 appears to represent the major independent factor affecting (V)DMSA uptake in breast cancer. Tumor size was the only independent parameter influencing MIBI uptake in breast cancer. (V)DMSA appears to have an advantage over MIBI in that it can be used to visualize tumors with intense proliferative activity, and thus it can identify those tumors that are more aggressive
Properties of Arctic liquid and mixed phase clouds from ship-borne Cloudnet observations during ACSE 2014
This study presents Cloudnet retrievals of Arctic clouds from measurements conducted during a 3-month research expedition along the Siberian shelf during summer and autumn 2014. During autumn, we find a strong reduction in the occurrence of liquid clouds and an increase for both mixed-phase and ice clouds at low levels compared to summer. About 80â% of all liquid clouds observed during the research cruise show a liquid water path below the infrared black body limit of approximately 50âgâmâ2. The majority of mixed-phase and ice clouds had an ice water path below 20âgâmâ2.
Cloud properties are analysed with respect to cloud-top temperature and boundary layer structure. Changes in these parameters have little effect on the geometric thickness of liquid clouds while mixed-phase clouds during warm-air advection events are generally thinner than when such events were absent. Cloud-top temperatures are very similar for all mixed-phase clouds. However, more cases of lower cloud-top temperature were observed in the absence of warm-air advection.
Profiles of liquid and ice water content are normalized with respect to cloud base and height. For liquid water clouds, the liquid water content profile reveals a strong increase with height with a maximum within the upper quarter of the clouds followed by a sharp decrease towards cloud top. Liquid water content is lowest for clouds observed below an inversion during warm-air advection events. Most mixed-phase clouds show a liquid water content profile with a very similar shape to that of liquid clouds but with lower maximum values during events with warm air above the planetary boundary layer. The normalized ice water content profiles in mixed-phase clouds look different from those of liquid water content. They show a wider range in maximum values with the lowest ice water content for clouds below an inversion and the highest values for clouds above or extending through an inversion. The ice water content profile generally peaks at a height below the peak in the liquid water content profile â usually in the centre of the cloud, sometimes closer to cloud base, likely due to particle sublimation as the crystals fall through the cloud
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