Analysis and correction of the magnetic field effects in the Hybrid Photo-Detectors of the RICH2 Ring Imaging Cherenkov detector of LHCb

The Ring Imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN are equipped with Hybrid Photo-Detectors. These vacuum photo-detectors are affected by the stray magnetic field of the LHCb magnet, which degrades their imaging properties. This effect increases the error on the Cherenkov angle measurement and would reduce the particle identification capabilities of LHCb. A system has been developed for the RICH2 Ring Imaging Cherenkov detector to perform a detailed characterisation of the magnetic distortion effects. It is described, along with the methods implemented to correct for these effects, restoring the optimal resolution.Comment: 16 pages, 11 figure

From cell lines to pluripotent Stem Cells for Modelling Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by loss of dopaminergic (DAergic) neurons in the substantia nigra that contributes to the main motor symptoms of the disease. At present, even if several advancements have been done in the last decades, the molecular and cellular mechanisms involved in the pathogenesis are far to be fully understood. Accordingly, the establishment of reliable in vitro experimental models to investigate the early events of the pathogenesis represents a key issue in the field. However, to mimic and reproduce in vitro the complex neuronal circuitry involved in PD-associated degeneration of DAergic neurons still remains a highly challenging issue. Here we will review the in vitro PD models used in the last 25 years of research, ranging from cell lines, primary rat or mice neuronal cultures to the more recent use of human induced pluripotent stem cells (hiPSCs) and, finally, the development of 3D midbrain organoids

From Protecting the Heart to Improving Athletic Performance - the Benefits of Local and Remote Ischaemic Preconditioning

Remote Ischemic Preconditioning (RIPC) is a non-invasive cardioprotective intervention that involves brief cycles of limb ischemia and reperfusion. This is typically delivered by inflating and deflating a blood pressure cuff on one or more limb(s) for several cycles, each inflation-deflation being 3-5 min in duration. RIPC has shown potential for protecting the heart and other organs from injury due to lethal ischemia and reperfusion injury, in a variety of clinical settings. The mechanisms underlying RIPC are under intense investigation but are just beginning to be deciphered. Emerging evidence suggests that RIPC has the potential to improve exercise performance, via both local and remote mechanisms. This review discusses the clinical studies that have investigated the role of RIPC in cardioprotection as well as those studying its applicability in improving athletic performance, while examining the potential mechanisms involved

Phylogenetic distance does not predict competition in green algal communities

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116355/1/ecs214005021.pd

How Does Restored Habitat For Chinook Salmon ( Oncorhynchus Tshawytscha ) In The Merced River In California Compare With Other Chinook Streams?

The amount of time and money spent on restoring rivers for declining populations of salmon has grown substantially in recent decades. But despite the infusion of resources, many studies suggest that salmon populations are continuing to decline, leading some to question the effectiveness of restoration efforts. Here we examine whether a particular form of salmon restoration—channel reconfiguration with gravel augmentation—generates physical and biological habitat that is comparable with other streams that support salmon. We compared a suite of habitat features known to influence the various life stages of Chinook salmon in a restoration project in California's Merced River with 19 other streams that also support Chinook that we surveyed in the same geographic region. Our survey showed that riffle habitats in the restored site of the Merced River have flow discharge and depth, substrate and food web characteristics that cannot be distinguished from other streams that support Chinook, suggesting that these factors are unlikely to be bottlenecks to salmon recovery in the Merced. However, compared with other streams in the region, the Merced has minimal riparian cover, fewer undercut banks, less woody debris and higher water temperatures, suggesting that these factors might limit salmon recovery. After identifying aspects in the Merced that differ from other streams, we used principal components analysis to correlate salmon densities to independent axes of environmental variation measured during our survey. These analyses suggested that salmon densities tend to be greatest in streams that have more undercut banks and woody debris and lower water temperatures. These are the same environmental factors that appear to be missing from the Merced River restoration effort. Collectively, our results narrow the set of candidate factors that may limit salmon recovery in channel reconfiguration restoration efforts. Copyright © 2012 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97512/1/rra1604.pd

The DSF Quorum Sensing System Controls the Positive Influence of Stenotrophomonas maltophilia on Plants

none7siopenAlavi P.; Muller H.; Cardinale M.; Zachow C.; Sanchez M.B.; Martinez J.L.; Berg G.Alavi, P.; Muller, H.; Cardinale, M.; Zachow, C.; Sanchez, M. B.; Martinez, J. L.; Berg, G

Diversity and community biomass depend on dispersal and disturbance in microalgal communities

The evidence for species diversity effects on ecosystem functions is mainly based on studies not explicitly addressing local or regional processes regulating coexistence or the importance of community structure in terms of species evenness. In experimental communities of marine benthic microalgae, we altered the successional stages and thus the strength of local species interactions by manipulating rates of dispersal and disturbance. The treatments altered realized species richness, evenness and community biomass. For species richness, dispersal mattered only at high disturbance rates; when opening new space, dispersal led to maximized richness at intermediate dispersal rates. Evenness, in contrast, decreased with dispersal at low or no disturbance, i.e. at late successional stages. Community biomass showed a nonlinear hump-shaped response to increasing dispersal at all disturbance levels.We found a positive correlation between richness and biomass at early succession, and a strong negative correlation between evenness and biomass at late succession. In early succession both community biomass and richness depend directly on dispersal from the regional pool, whereas the late successional pattern shows that if interactions allow the most productive species to become dominant, diverting resources from this species (i.e. higher evenness) reduces production. Our study emphasizes the difference in biodiversity–function relationships over time, as different mechanisms contribute to the regulation of richness and evenness in early and late successional stages

The FXR agonist obeticholic acid inhibits the cancerogenic potential of human cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive cancer with high resistance to chemotherapeutics. CCA is enriched in cancer stem cells, which correlate with aggressiveness and prognosis. FXR, a member of the metabolic nuclear receptor family, is markedly down-regulated in human CCA. Our aim was to evaluate, in primary cultures of human intrahepatic CCA (iCCA), the effects of the FXR agonist obeticholic acid (OCA), a semisynthetic bile acid derivative, on their cancerogenic potential. Primary human iCCA cell cultures were prepared from surgical specimens of mucinous or mixed iCCA subtypes. Increasing concentrations (0–2.5 μM) of OCA were added to culture media and, after 3–10 days, effects on proliferation (MTS assay, cell population doubling time), apoptosis (annexin V-FITC/propidium iodide), cell migration and invasion (wound healing response and Matrigel invasion assay), and cancerogenic potential (spheroid formation, clonogenic assay, colony formation capacity) were evaluated. Results: FXR gene expression was downregulated (RT-qPCR) in iCCA cells vs normal human biliary tree stem cells (p < 0.05) and in mucinous iCCA vs mixed iCCA cells (p < 0.05) but was upregulated by addition of OCA. OCA significantly (p < 0.05) inhibited proliferation of both mucinous and mixed iCCA cells, starting at a concentration as low as 0.05 μM. Also, CDCA (but not UDCA) inhibited cell proliferation, although to a much lower extent than OCA, consistent with its different affinity for FXR. OCA significantly induced apoptosis of both iCCA subtypes and decreased their in vitro cancerogenic potential, as evaluated by impairment of colony and spheroid formation capacity and delayed wound healing and Matrigel invasion. In general, these effects were more evident in mixed than mucinous iCCA cells. When tested together with Gemcitabine and Cisplatin, OCA potentiated the anti-proliferative and pro-apoptotic effects of these chemotherapeutics, but mainly in mixed iCCA cells. OCA abolished the capacity of both mucinous and mixed iCCA cells to form colonies when administered together with Gemcitabine and Cisplatin. In subcutaneous xenografts of mixed iCCA cells, OCA alone or combined with Gemcitabine or Cisplatin markedly reduced the tumor size after 5 weeks of treatment by inducing necrosis of tumor mass and inhibiting cell proliferation. In conclusion, FXR is down-regulated in iCCA cells, and its activation by OCA results in anti-cancerogenic effects against mucinous and mixed iCCA cells, both in vitro and in vivo. The effects of OCA predominated in mixed iCCA cells, consistent with the lower aggressiveness and the higher FXR expression in this CCA subtype. These results, showing the FXR-mediated capacity of OCA to inhibit cholangiocarcinogenesis, represent the basis for testing OCA in clinical trials of CCA patients

A computer simulation protocol to assess the accuracy of a Radio Stereometric Analysis (RSA) image processor according to the ISO-5725

Radio-Stereometric-Analysis and x-ray fluoroscopy are radiological techniques that require dedicated software to process data. The accurate calibration of these software is therefore critical. The aim of this work is to produce a protocol for evaluating the softwares' accuracy according to the ISO-5725. A series of computer simulations of the radiological setup and images were employed. The noise level of the images was also changed to evaluate the accuracy with different image qualities. The protocol was tested on a custom software developed by the authors. Radiological scene reconstruction accuracy was of (0.092 +- 0.14) mm for tube position, and (0.38 +- 0.31) mm / (2.09 +- 1.39) deg for detectors oriented in a direction other than the source-detector direction. In the source-detector direction the accuracy was of (2.68 +- 3.08) mm for tube position, and of (0.16 +- 0.27) mm / (0.075 +- 1.16) deg for the detectors. These disparate results are widely discussed in the literature. Model positioning and orientation was also highly accurate: (0.22 +- 0.46) mm / (0.26 +- 0.22) deg. Accuracy was not affected by the noise level. The protocol was able to assess the accuracy of the RSA system. It was also useful to detect and fix hidden bugs. It was also useful to detect and resolve hidden bugs in the software, and in optimizing the algorithms