1,562 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
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Structure in mind, structure in vocal tract
We update our understanding of the view that grammar regulates intersegmental temporal coordination and present an extension of that view to a new domain: we argue that inter-segmental coordination is basic to prosody. It is the glue joining segments together differently in different languages (here, illustrated with examples from Arabic and Spanish) and orchestrates their unfolding in ways corresponding to constructs posited in theoretical analysis. The correspondence is one between organization in mind-brain and organization in vocal tract. Moreover, for both mind-brain and vocal tract, the organization is phonological and abstract. It is so because it holds over segments of various identities: in Arabic, the first segment in /bka/ is not prosodified as part of the same unit as /ka/ and this holds true also for /blat/, /klat/ and so on, regardless of sonority. In contrast, in English or Spanish, a different organization holds. Crucially, uniformity in organization (same organization presiding over sequences with varying segmental makeup) does not imply uniqueness of phonetic exponents: prosodic organization is pleiotropic, simultaneously expressed by more than one phonetic exponent. Finally, two properties of coordination relations are underscored: lawful flexibility and abstractness. The first is revealed in the degrees of freedom with which movements corresponding to any given effector begin; the second in invariances of task-relevant kinematic signatures regardless of the effectors implicated in any given segmental sequence. Once again, abstract phonological structure is mirrored in vocal tracts via coordination relations holding across physiology and the particular modes of its operation
Asymmetric Silver to Oxide Adhesion in Multilayers Deposited on Glass by Sputtering
We have developed a wedge-loaded double-cantilever beam adhesion measurement
set-up for thin films deposited on glass by sputtering. The test is described
in details. Results on the Glass/sublayer/Ag/ZnO multilayer provide evidence
that \SnOd or \TiOd perform better than ZnO as a sublayer. Then however,
rupture within the multilayer shifts to the upper Ag/ZnO interface. The latter
is shown to be tougher than the lower ZnO/Ag interface, an asymmetry due to
non-equilibrium interfacial structures
Aerosol-cloud interactions in the NASA GMI: model development and indirect forcing assessments
International audienceThis study uses the NASA Global Modeling Initiative (GMI) 3-D chemical transport model (CTM) for assessments of indirect forcing and its sensitivity to the treatment of aerosol, aerosol-cloud interactions and meteorological fields. Three different meteorological datasets from NASA Data Assimilation Office (DAO), NASA finite volume GCM (FVGCM) and the Goddard Institute for Space Studies version II' (GISS II') GCM were used. GMI is ideal for this study as different model components (such as meteorological fields and chemical mechanisms) can easily be interchanged under the same model framework to capture the first aerosol indirect effect (AIE), and its sensitivity to parameterizations and meteorological fields. Cloud droplet number concentration was calculated by implementing both diagnostic and physically based droplet parameterizations. Derived cloud properties, such as cloud optical thickness and effective radius were compared with the remotely sensed data from Moderate Resolution Imaging Spectroradiometer (MODIS). GMI was able to capture the spatial variability and the land-ocean contrast observed in the satellite record. Depending on the meteorological field and droplet parameterization used, the annual mean first AIE ranged from ?0.99 to ?1.48 W m?2. It is found that, roughly 80% of the variation is attributed to changes in the meteorology (primarily from variations in liquid water path), while the remaining 20% is attributed to different cloud droplet parameterizations
Προσομοίωση του υπόγειου παράκτιου υδροφορέα της Μεσαριάς στη Σαντορίνη
102 σ.Ο υπόγειος παράκτιος υδροφορέας της Μεσαριάς στην Σαντορίνη αποτελεί την κύρια πηγή για την κάλυψη των αναγκών του νησιού. Λόγω των αυξημένων αντλήσεων στην περιοχή τα υπόγεια νερά συνεχώς υποβαθμίζονται ποιοτικά με αποτέλεσμα την εισροή του θαλασσινού νερού στον υδροφορέα και την πιθανή υφαλμύρωση του. Σκοπός της παρούσας διπλωματικής εργασίας είναι η μελέτη του υπόγειου υδροφόρου συστήματος της Σαντορίνης. Συγκεκριμένα, γίνεται προσομοίωση της υπόγειας ροής και εξετάζονται διάφορα σενάρια μείωσης τροφοδοσίας και άντλησης καθώς και ένα σενάριο τεχνητού εμπλουτισμού προκειμένου να εξαχθούν χρήσιμα συμπεράσματα για την συμπεριφορά του υδροφορέα και να προταθούν λύσεις για την προστασία αυτού από το φαινόμενο της υφαλμύρωσης. Το μοντέλο προσομοίωσης της ροής που χρησιμοποιήθηκε, εφαρμόζεται σε παράκτιους φρεάτιους υδροφορείς σε συνθήκες μόνιμης ροής και βασίζεται στην θεώρηση της απότομης διεπιφάνειας αλμυρού-γλυκού νερού, στην προσέγγιση του Ghyben-Herzberg, στις παραδοχές της οριζόντιας ροής και στη ανάλυση του Strack. Η σχεδίαση και η εφαρμογή του έγινε στο PMWIN, όπου και υπολογίστηκε το δυναμικό φ, ενώ ο υπολογισμός του πιεζομετρικού φορτίου και το βάθος της διεπιφάνειας κάτω από το επίπεδο της θάλασσας έγιναν σε περιβάλλον Matlab Τα σενάρια άντλησης και τροφοδοσίας σχεδιαστήκαν με σκοπό την προστασία του υδροφορέα από την είσοδο του θαλασσινού νερού. Στα σενάρια αυτά αναζητήθηκε η βέλτιστη παροχή άντλησης ώστε να θεωρείται ασφαλής ο υδροφορέας, σύμφωνα με κάποιους περιορισμούς που είχαν τεθεί. Η εύρεση των βέλτιστων αυτών τιμών έγινε με δοκιμές.The coastal aquifer of Messaria in the island of Santorini consist the main source of the water supply in the area. Due to the increasing pumping in the area, the underground waters are continuously demoted, as far as their quality, something that leads to the influx of the sea water in the aquifer and possibly to its salinity. The goal of this research is the study of the underground of water wagon system in Santorini. More specifically, we apply a model of simulation of flow of coastal aquifer and we examine the different scenarios of reducing the recharge and pumping scenario. We also examine a scenario of artificial enrichment in order to estimate the attribute of the aquifer and find the solutions in order to avoid the problem of salinity. The model of simulation of flow that was used , is applied in coastal underground aquifers, in steady-state conditions and is based on the abrupt fresh-saltwater interface, on the Ghyben-Herzberg approximation, on the horizontal flow approximations and on Strack’s analysis. PMWIN program was used for the design and the application of the model and for the computing of potential φ. Matlab was used for the calculation of the hydraulic heads and the depth of the interface under the level of the sea. The scenarios of the pumping and the recharge were achieved in order to protect the aquifer from the influx of the sea water. In those scenarios, and according to some confinements, we searched for the best supply pumping in order to keep the aquifer safe. The search of those supplies was achieved with testing.Κωνσταντίνα Π. Σωτηροπούλο
Image processing applications: From particle physics to society
We present an embedded system for extremely efficient real-time pattern recognition execution, enabling technological advancements with both scientific and social impact. It is a compact, fast, low consumption processing unit (PU) based on a combination of Field Programmable Gate Arrays (FPGAs) and the full custom associative memory chip. The PU has been developed for real time tracking in particle physics experiments, but delivers flexible features for potential application in a wide range of fields. It has been proposed to be used in accelerated pattern matching execution for Magnetic Resonance Fingerprinting (biomedical applications), in real time detection of space debris trails in astronomical images (space applications) and in brain emulation for image processing (cognitive image processing). We illustrate the potentiality of the PU for the new applications
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 80 % of all liquid clouds observed during the research cruise show a liquid water path below the infrared black body limit of approximately 50 g m−2. The majority of mixed-phase and ice clouds had an ice water path below 20 g m−2.
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 – 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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EGF-R is Expressed and AP-1 and NF-κ:B Are Activated in Stromal Myofibroblasts Surrounding Colon Adenocarcinomas Paralleling Expression of COX-2 and VEGF
Background:: COX-2 and VEGF are important triggers of colon cancer growth, metastasis and angiogenesis. Cox-2 promoter contains transcriptional regulatory elements for AP-1 and NF-κ:B transcription factors whilst vegf is a known AP-1 downstream target gene. We investigated whether stromal myofibroblasts surrounding colon adenocarcinomas express COX-2 and VEGF and whether activation of AP-1 and NF-κ:B, as well as expression of EGF-R parallel expression of COX-2 and VEGF in these cells. Methods:: Immunohistochemical methodology was performed on archival sections from 40 patients with colon adenocarcinomas. We evaluated c-FOS, p-c-JUN (phosphorylated c-JUN), p-Iκ:B-α (phosphorylated Iκ:B-α), EGF-R, COX-2, NF-κ:B and VEGF expression in stromal myofibroblasts surrounding colon adenocarcinomas. Double immunostaining with a-smooth muscle actin and each antibody was done to verify the expression of these molecules in stromal myofibroblasts. Results:: VEGF, p-Iκ:B-α, NF-κ:B, c-FOS, p-c-JUN, EGF-R and COX-2 were expressed in stromal myofibroblasts surrounding colon adenocarcinomas in the majority of cases. EGF-R, p-Iκ:B-α, NF-κ:B, c-FOS and p-c-JUN correlated positively with COX-2 and VEGF expression. Conclusion:: Stromal myofibroblasts surrounding colon adenocarcinomas are an important source of VEGF and COX-2 production, while AP-1 and NF-κ:B transcription factors are activated and EGF-R is expressed in these cells and associated with COX-2 and VEGF production
Ancient encaustic: An experimental exploration of technology, ageing behaviour and approaches to analytical investigation
The composition of the ancient wax-based painting technique known as encaustic has long been the subject of debate. Ancient sources provide few details of the technology, and modern understanding of the medium is restricted to theoretical interpretation and experimental observation. In this multi-analytical collaborative study, a number of analytical approaches were used to investigate the physical and molecular properties of a range of experimentally prepared encaustic paints before and after ageing. Analysis using gas chromatography mass spectrometry, Fourier transform infrared spectroscopy (invasive and non-invasive), X-ray diffraction and thermogravimetric analysis demonstrated how differences in the technology of production alter the properties and composition of the medium and showed how these are modified by the addition of pigment and the effects of ageing. Comparison of results from the different analytical techniques highlights the benefit of an integrated analytical approach to the analysis of ancient encaustic paints and the fundamental importance of insights from invasive study to evaluating the results of non-invasive analysis
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