The antioxidant properties of Ce-containing bioactive glass nanoparticles explained by Molecular Dynamics simulations

Molecular dynamics simulations of two glass nanoparticles with composition 25Na2O·25CaO 50SiO2 mol% (Ce-K NP) and 46.1SiO2·24.4Na2O·26.9CaO· 2.6P2O5 mol.% (Ce-BG NP) doped with 3.6 mol% of CeO2 have been carried out in order to explain the enhanced antioxidant properties of the former glass with respect to the latter. The present models show that the different catalase mimetic activity of the two NPs is related to the Ce3+/Ce4+ ratio exposed at their surface. In fact, this ratio is about 3.5 and 13 in the bulk and at the surface of the Ce-BG NP, and 1.0 and 2.1 in the bulk and at the surface of the Ce-K NPs, respectively. Since both oxidation states are necessary for the catalysis of the dismutation reaction of hydrogen peroxides, NPs with a very high Ce3+/Ce4+ ratio possess poorer antioxidant properties. Moreover, our simulations reveal that the already low silicate connectivity found in the bulk glasses examined here is further reduced on the nanoparticle surface, whereas the Na+/Ca2+ ratio rapidly increases. Sodium, calcium and cerium sites in proximity of the surface are found to be under-coordinated, prone to quickly react with water present in physiological environments, thus accelerating the glass biodegradatio

Sensitive CO and 13CO survey of water fountain stars Detections towards IRAS 18460-0151 and IRAS 18596+0315

 This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this recordContext. Water fountain stars represent a stage between the asymptotic giant branch (AGB) and planetary nebulae phases, when the mass loss changes from spherical to bipolar. These types of evolved objects are characterized by high-velocity jets in the 22 GHz water maser emission. Aims. The objective of this work is to detect and study in detail the circumstellar gas in which the bipolar outflows are emerging. The detection and study of thermal lines may help in understanding the nature and physics of the envelopes in which the jets are developing. Methods. We surveyed the CO and 13CO line emission towards a sample of ten water fountain stars through observing the J = 1 → 0 and 2 → 1 lines of CO and 13CO, using the 30 m IRAM radio-telescope at Pico Veleta. All the water fountains visible from the observatory were surveyed. Results. Most of the line emission arises from foreground or background Galactic clouds, and we had to thoroughly analyse the spectra to unveil the velocity components related to the stars. In two sources, IRAS 18460-0151 and IRAS 18596+0315, we identified wide velocity components with a width of 35 - 40 km s-1 that are centred at the stellar velocities. These wide components can be associated with the former AGB envelope of the progenitor star. A third case, IRAS 18286-0959, is reported as tentative; in this case a pair of narrow velocity components, symmetrically located with respect to the stellar velocity, have been discovered. We also modelled the line emission using an LVG code and derived some global physical parameters, which allowed us to discuss the possible origin of this gas in relation to the known bipolar outflows. For IRAS 18460-0151 and IRAS 18596+0315, we derived molecular masses close to 0.2 M⊙, mean densities of 104 cm-3, and mass-loss rates of 10 -4 M⊙ yr-1. The kinetic temperatures are rather low, between 10 and 50 K in both cases, which suggests that the CO emission is arising from the outer and cooler regions of the envelopes. No fitting was possible for IRAS 18286-0959, because line contamination can not be discarded in this case. Conclusions. The molecular masses, mean densities, and mass-loss rates estimated for the circumstellar material associated with IRAS 18460-0151 and IRAS 18596+0315 confirm that these sources are at the end of the AGB or the beginning of the post-AGB evolutionary stages. The computed mass-loss rates are among the highest ones possible according to current evolutionary models, which leads us to propose that the progenitors of these water fountains had masses in the range from 4 to 8 M ⊙. We speculate that CO emission is detected in water fountains as a result of a CO abundance enhancement caused by current episodes of low-collimation mass-loss. © ESO, 2013.MICINNJunta de Andalucí

The Trouble with the Weather: a southern response

Research Background At a time when global warming was both urgent and overwhelming, there was a dearth of exhibitions dedicated to the issue that made room for audiences to engage in new ways. There was a need to bring together a range of art works that spoke to the issue, to an exhibition space, and to each other in ways that allowed people (new) ways to engage with global warming, to find their own ways of thinking and responding. As global warming was an emotionally and politically overloaded topic, there was a need for non-didactic exhibitions that opened thinking up as to how the uneasy relationship between technology, nature and culture was being unsettled once more. Research Contribution The artists in the Trouble with the Weather responded to weather events and to the weather as event -- psychically, 'pataphysically, emotionally and aesthetically in ways that opened the issue up for audiences. It featured a range of significant southern hemisphere artists including Elizabeth Day, David Haines & Joyce Hinterding (Aus), Jonathan Jones, Zina Kaye, Dani Marti, Janine Randerson, Te Vaka, John Tonkin and H J Wedge. Research Significance The importance of the exhibition (and its catalogue) was demonstrated by the funding it gained from Luca Belgiorno-Nettis, UTS, City of Sydney and the Australia Council for the Arts. It was featured and reviewed in SMH, RealTime and Loop Magazine. "Despite the undercurrent of urgency and desperation in the subject matter, many of the works took a whimsical approach, from Dani Marti's suburban kitsch sculpture made from pool noodles to Joyce Hinterding's beautiful ink splattered diagrams for cloud engineering and, of course, Neumark and Miranda's own contribution. Consequently, and without stridency, the overarching issues operate as a kind of climate in which the works can dwell and evolve." Gail Priest, RealTme 80, 2007. The catalogue was acquired by the Guggenheim Museum, NYC

Impurity-enhanced solid-state amorphization : the Ni-Si thin film reaction altered by nitrogen

Solid-state amorphization, the growth of an amorphous phase during annealing, has been studied in a wide variety of thin film structures. Whereas research on the remarkable growth of such a metastable phase has mostly focused on strictly binary systems, far less is known about the influence of impurities on such reactions. In this paper, the influence of nitrogen, introduced via ion implantation, is studied on the solid-state amorphization reaction of thin (35 nm) Ni films with Si, using in situ x-ray diffraction (XRD), ex situ Rutherford backscattering spectrometry, XTEM, and synchrotron XRD. It is shown that due to small amounts of nitrogen (<2 at.%), an amorphous Ni-Si phase grows almost an order of magnitude thicker during annealing than for unimplanted samples. Nitrogen hinders the nucleation of the first crystalline phases, leading to a new reaction path: the formation of the metal-rich crystalline silicides is suppressed in favour of an amorphous Ni-Si alloy; during a brief temperature window between 330 and 350 degrees C, the entire film is converted to an amorphous phase. The first crystalline structure to grow is the orthorhombic NiSi phase. We demonstrate that this impurity-enchanced solid-state amorphization reaction occurs only under specific implantation conditions. In particular, the initial distribution of nitrogen upon implantation is crucial: sufficient nitrogen impurities must be present at the interface throughout the reaction. Introducing implantation damage without nitrogen impurities (e.g. by implanting a noble gas) does not cause the enhanced solid-state amorphization reaction. Moreover, we show that the stabilizing effect of nitrogen on amorphous Ni-Si films (with a composition ranging from 40% to 50% Si) is not restricted to thin film reactions, but is a general feature of the Ni-Si system

Ureterolithiasis after Cohen re-implantation – case report

BACKGROUND: In the past decades, the widespread use of cross-trigonal ureteral reimplants for the treatment of children with vesicoureteral reflux has resulted in a large population of patients with transversely lying ureters. As this population gets older they will consequently be entering an age group at higher risk for stone and urothelial cancer formation. If ureteroscopy becomes necessary, the transverse position of the ureter makes ureteric access often impossible. CASE PRESENTATION: We present the case of a young man who not only suffered from urolithiasis due to hyperparathyroidism, but also further jeopardized his treatment by omitting the fact that as a child he underwent Cohen reimplantation of the right ureter. CONCLUSIONS: This case illustrates the particular difficulties the endoscopist may face in this group of patients. Patients with difficult ureteric access, abnormal anatomy, or those with known cross-trigonal ureteric reimplantations should be managed in a specialised endourology unit

Arsenic Exposure and Hypertension: A Systematic Review

Background: Environmental exposure to arsenic has been linked to hypertension in persons living in arsenic-endemic areas

The information needs of people living with ankylosing spondylitis: a questionnaire survey

&lt;p&gt;BACKGROUND:Today, health care is patient-centred with patients more involved in medical decision making and taking an active role in managing their disease. It is important that patients are appropriately informed about their condition and that their health care needs are met. We examine the information utilisation, sources and needs of people with ankylosing spondylitis (AS).&lt;/p&gt; &lt;p&gt;METHODS: Participants in an existing AS cohort study were asked to complete a postal or online questionnaire containing closed and open-ended questions, regarding their information access and needs. Participants were stratified by age and descriptive statistics were performed using STATA 11, while thematic analysis was performed on open-ended question narratives. Qualitative data was handled in Microsoft Access and explored for emerging themes and patterns of experiences.&lt;/p&gt; &lt;p&gt;RESULTS: Despite 73% of respondents having internet access, only 49% used the internet to access information regarding AS. Even then, this was only infrequently. Only 50% of respondents reported accessing written information about AS, which was obtained mainly in specialist clinics. Women were more likely than men to access information (63% (women) 46% (men)) regardless of the source, while younger patients were more likely to use online sources. The main source of non-written information was the rheumatologist. Overall, the respondents felt there was sufficient information available, but there was a perception that the tone was often too negative. The majority (95%) of people would like to receive a regular newsletter about AS, containing positive practical and local information. Suggestions were also made for more information about AS to be made available to non-specialist medical professionals and the general public.&lt;/p&gt; &lt;p&gt;CONCLUSIONS: There appears to be sufficient information available for people with AS in the UK and this is mostly accessed by younger AS patients. Many patients, particularly men, choose not to access AS information and concerns were raised about its negative tone. Patients still rely on written and verbal information from their specialists. Future initiatives should focus on the delivery of more positive information, targeting younger participants in particular and increasing the awareness in the general population and wider non-specialist medical community.&lt;/p&gt

An insight into the sialotranscriptome of the brown dog tick, Rhipicephalus sanguineus

<p>Abstract</p> <p>Background</p> <p><it>Rhipicephalus sanguineus</it>, known as the brown dog tick, is a common ectoparasite of domestic dogs and can be found worldwide. <it>R.</it><it>sanguineus </it>is recognized as the primary vector of the etiological agent of canine monocytic ehrlichiosis and canine babesiosis. Here we present the first description of a <it>R. sanguineus </it>salivary gland transcriptome by the production and analysis of 2,034 expressed sequence tags (EST) from two cDNA libraries, one consctructed using mRNA from dissected salivary glands from female ticks fed for 3-5 days (early to mid library, RsSGL1) and the another from ticks fed for 5 days (mid library, RsSGL2), identifying 1,024 clusters of related sequences.</p> <p>Results</p> <p>Based on sequence similarities to nine different databases, we identified transcripts of genes that were further categorized according to function. The category of putative housekeeping genes contained ~56% of the sequences and had on average 2.49 ESTs per cluster, the secreted protein category contained 26.6% of the ESTs and had 2.47 EST's/clusters, while 15.3% of the ESTs, mostly singletons, were not classifiable, and were annotated as "unknown function". The secreted category included genes that coded for lipocalins, proteases inhibitors, disintegrins, metalloproteases, immunomodulatory and antiinflammatory proteins, as Evasins and Da-p36, as well as basic-tail and 18.3 kDa proteins, cement proteins, mucins, defensins and antimicrobial peptides. Comparison of the abundance of ESTs from similar contigs of the two salivary gland cDNA libraries allowed the identification of differentially expressed genes, such as genes coding for Evasins and a thrombin inhibitor, which were over expressed in the RsSGL1 (early to mid library) versus RsSGL2 (mid library), indicating their role in inhibition of inflammation at the tick feeding site from the very beginning of the blood meal. Conversely, sequences related to cement (64P), which function has been correlated with tick attachment, was largely expressed in the mid library.</p> <p>Conclusions</p> <p>Our survey provided an insight into the <it>R. sanguineus </it>sialotranscriptome, which can assist the discovery of new targets for anti-tick vaccines, as well as help to identify pharmacologically active proteins.</p

Estudio de seguridad vial sobre el tramo de la carretera Tipitapa - Masaya Nic-11a, empalme petronic km 20+780 hasta el km 24 carretera Tipitapa - Masaya

Es una investigación dirigida a analizar las causas de los accidentes de tránsito ocurridos en este tramo urbano del municipio de Tipitapa y para esto se desarrollaron todos los análisis correspondientes para el estudio. A, (empalme Petronic km 20+780 hasta el km 24 carretera Tipitapa-Masaya