SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/\mu m. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteriorating is not independent on particles' stopping power, thus illustrating that the radiation hardness of plastic scintillators can be strongly weakened under high excitation density in heavy ion environments.Comment: 5 figures, accepted in Nucl. Instrum. Methods

Quantifying Microstructural Evolution in Moving Magma

Many of the grand challenges in volcanic and magmatic research are focused on understanding the dynamics of highly heterogeneous systems and the critical conditions that enable magmas to move or eruptions to initiate. From the formation and development of magma reservoirs, through propagation and arrest of magma, to the conditions in the conduit, gas escape, eruption dynamics, and beyond into the environmental impacts of that eruption, we are trying to define how processes occur, their rates and timings, and their causes and consequences. However, we are usually unable to observe the processes directly. Here we give a short synopsis of the new capabilities and highlight the potential insights that in situ observation can provide. We present the XRheo and Pele furnace experimental apparatus and analytical toolkit for the in situ X-ray tomography-based quantification of magmatic microstructural evolution during rheological testing. We present the first 3D data showing the evolving textural heterogeneity within a shearing magma, highlighting the dynamic changes to microstructure that occur from the initiation of shear, and the variability of the microstructural response to that shear as deformation progresses. The particular shear experiments highlighted here focus on the effect of shear on bubble coalescence with a view to shedding light on both magma transport and fragmentation processes. The XRheo system is intended to help us understand the microstructural controls on the complex and non-Newtonian evolution of magma rheology, and is therefore used to elucidate the many mobilization, transport, and eruption phenomena controlled by the rheological evolution of a multi-phase magmatic flows. The detailed, in situ characterization of sample textures presented here therefore represents the opening of a new field for the accurate parameterization of dynamic microstructural control on rheological behavior

Haemostatics in surgery and our experience in the enucleoresection of renal cell carcinoma

<p>Abstract</p> <p>Background</p> <p>30 patients, with T1 renal cell carcinomas (RCC) who underwent open enucleoresection of the tumour, were randomized to the use of a topical haemostatic agent (Floseal) or to an infrared-sapphire coagulator (ISC), to compare their efficacy in achieving haemostasis. Methods: Successful intra-operative haemostasis, intra- and post-operative bleeding, operative time, hospital discharge were evaluated.</p> <p>Results</p> <p>Statistically higher rates of successful haemostasis and shorter time-to-haemostasis (8,1 vs 12,9 min) were observed in the FloSeal group (p < 0.001 both). Patients operative time was not different between Group 1 vs 2 (58.7 ± 12 vs 62.4 ± 15; p > 0.05). The average blood loss during surgery was less (60 +/- 25.5 mL) for the FloSeal group than for the ISC group (85 +/- 40.5 mL) (p < 0.05). Postoperative blood loss was 25 +/- 5 mL and 40 +/- 45 mL for Floseal and ISC respectively, (p < 0.05). Length of the postoperative hospital discharge was 2.5 +/- 1.2 days for FloSeal group and 3.5 +/- 1.3 for the Group 2 (p < 0.05). No major immediate or delayed complications were observed in either Groups.</p> <p>Conclusions</p> <p>The use of Floseal and ISC offer a safe and efficacy haemostasis in the enucleoresection of RCC. Moreover, our results show a less intra-operative and post-operative blood loss as well as a shorter time to haemostasis of Floseal in respect to ISC.</p

Dominating Clasp of the Financial Sector Revealed by Partial Correlation Analysis of the Stock Market

What are the dominant stocks which drive the correlations present among stocks traded in a stock market? Can a correlation analysis provide an answer to this question? In the past, correlation based networks have been proposed as a tool to uncover the underlying backbone of the market. Correlation based networks represent the stocks and their relationships, which are then investigated using different network theory methodologies. Here we introduce a new concept to tackle the above question—the partial correlation network. Partial correlation is a measure of how the correlation between two variables, e.g., stock returns, is affected by a third variable. By using it we define a proxy of stock influence, which is then used to construct partial correlation networks. The empirical part of this study is performed on a specific financial system, namely the set of 300 highly capitalized stocks traded at the New York Stock Exchange, in the time period 2001–2003. By constructing the partial correlation network, unlike the case of standard correlation based networks, we find that stocks belonging to the financial sector and, in particular, to the investment services sub-sector, are the most influential stocks affecting the correlation profile of the system. Using a moving window analysis, we find that the strong influence of the financial stocks is conserved across time for the investigated trading period. Our findings shed a new light on the underlying mechanisms and driving forces controlling the correlation profile observed in a financial market

Host Sexual Dimorphism and Parasite Adaptation

Disease expression and prevalence often vary in the different sexes of the host. This is typically attributed to innate differences of the two sexes but specific adaptations by the parasite to one or other host sex may also contribute to these observations

Putative role of the adenosine A3 receptor in the antiproliferative action of N6-(2-isopentenyl)adenosine

We tested a panel of naturally occurring nucleosides for their affinity towards adenosine receptors. Both N6-(2-isopentenyl)adenosine (IPA) and racemic zeatin riboside were shown to be selective human adenosine A3 receptor (hA3R) ligands with affinities in the high nanomolar range (Ki values of 159 and 649 nM, respectively). These values were comparable to the observed Ki value of adenosine on hA3R, which was 847 nM in the same radioligand binding assay. IPA also bound with micromolar affinity to the rat A3R. In a functional assay in Chinese hamster ovary cells transfected with hA3R, IPA and zeatin riboside inhibited forskolin-induced cAMP formation at micromolar potencies. The effect of IPA could be blocked by the A3R antagonist VUF5574. Both IPA and reference A3R agonist 2-chloro-N6-(3-iodobenzyl)adenosine-5′-N-methylcarboxamide (Cl-IB-MECA) have known antitumor effects. We demonstrated strong and highly similar antiproliferative effects of IPA and Cl-IB-MECA on human and rat tumor cell lines LNCaP and N1S1. Importantly, the antiproliferative effect of low concentrations of IPA on LNCaP cells could be fully blocked by the selective A3R antagonist MRS1523. At higher concentrations, IPA appeared to inhibit cell growth by an A3R-independent mechanism, as was previously reported for other A3R agonists. We used HPLC to investigate the presence of endogenous IPA in rat muscle tissue, but we could not detect the compound. In conclusion, the antiproliferative effects of the naturally occurring nucleoside IPA are at least in part mediated by the A3R