Environmental study of a Micromegas detector

We report on measurements of the basic performance of a Micromegas detector for a digital hadronic calorimeter. Electron collection efficiency, energy resolution and gas gain were measured in various mixtures of Ar and CO2. Also the dependence of the gain on environmental variables (pressure, temperature), gas parameters (flow, mixing ratio) and geometry (amplication gap size) is studied. Eventually, predictions on the impact of these variables on the detection efficiency of thin Micromegas detectors are drawn

Status of the Micromegas semi-DHCAL

The activities towards the fabrication and test of a 1 m3 semi-digital hadronic calorime- ter are reviewed. The prototype sampling planes would consist of 1 m2 Micromegas chambers with 1 cm2 granularity and embedded 2 bits readout suitable for PFA calorime- try at an ILC detector. The design of the 1 m2 chamber is presented first, followed by an overview of the basic performance of small prototypes. The basic units composing the 1 m2 chamber are 32 \times 48 cm2 boards with integrated electronics and a micro-mesh. Results of character- ization tests of such boards are shown. Micromegas as a proportional detector is well suited for semi-digital hadronic calorimetry. In order to quantify the gain in perfor- mance when using one or more thresholds, simulation studies are being carried out, some of which will be reported in this contribution

Learning Interpretable Temporal Properties from Positive Examples Only

We consider the problem of explaining the temporal behavior of black-boxsystems using human-interpretable models. To this end, based on recent researchtrends, we rely on the fundamental yet interpretable models of deterministicfinite automata (DFAs) and linear temporal logic (LTL) formulas. In contrast tomost existing works for learning DFAs and LTL formulas, we rely on onlypositive examples. Our motivation is that negative examples are generallydifficult to observe, in particular, from black-box systems. To learnmeaningful models from positive examples only, we design algorithms that relyon conciseness and language minimality of models as regularizers. To this end,our algorithms adopt two approaches: a symbolic and a counterexample-guidedone. While the symbolic approach exploits an efficient encoding of languageminimality as a constraint satisfaction problem, the counterexample-guided onerelies on generating suitable negative examples to prune the search. Both theapproaches provide us with effective algorithms with theoretical guarantees onthe learned models. To assess the effectiveness of our algorithms, we evaluateall of them on synthetic data.<br

Test in a beam of large-area Micromegas chambers for sampling calorimetry

Application of Micromegas for sampling calorimetry puts specific constraints on the design and performance of this gaseous detector. In particular, uniform and linear response, low noise and stability against high ionisation density deposits are prerequisites to achieving good energy resolution. A Micromegas-based hadronic calorimeter was proposed for an application at a future linear collider experiment and three technologically advanced prototypes of 1$\times$1 m$^{2}$ were constructed. Their merits relative to the above-mentioned criteria are discussed on the basis of measurements performed at the CERN SPS test-beam facility

Tuning the polymorphism of the anti-VEGF G-rich V7t1 aptamer by covalent dimeric constructs

In the optimization process of nucleic acid aptamers, increased affinity and/or activity are generally searched by exploring structural analogues of the lead compound. In many cases, promising results have been obtained by dimerization of the starting aptamer. Here we studied a focused set of covalent dimers of the G-quadruplex (G4) forming anti-Vascular Endothelial Growth Factor (VEGF) V7t1 aptamer with the aim of identifying derivatives with improved properties. In the design of these covalent dimers, connecting linkers of different chemical nature, maintaining the same polarity along the strand or inverting it, have been introduced. These dimeric aptamers have been investigated using several biophysical techniques to disclose the conformational behavior, molecularity and thermal stability of the structures formed in different buffers. This in-depth biophysical characterization revealed the formation of stable G4 structures, however in some cases accompanied by alternative tridimensional arrangements. When tested for their VEGF165 binding and antiproliferative activity in comparison with V7t1, these covalent dimers showed slightly lower binding ability to the target protein but similar if not slightly higher antiproliferative activity on human breast adenocarcinoma MCF-7 cells. These results provide useful information for the design of improved dimeric aptamers based on further optimization of the linker joining the two consecutive V7t1 sequences

Loading of Polydimethylsiloxane with a Human ApoB-Derived Antimicrobial Peptide to Prevent Bacterial Infections

Background: medical device-induced infections affect millions of lives worldwide and innovative preventive strategies are urgently required. Antimicrobial peptides (AMPs) appear as ideal candidates to efficiently functionalize medical devices surfaces and prevent bacterial infections. In this scenario, here, we produced antimicrobial polydimethylsiloxane (PDMS) by loading this polymer with an antimicrobial peptide identified in human apolipoprotein B, r(P)ApoBLPro. Methods: once obtained loaded PDMS, its structure, anti-infective properties, ability to release the peptide, stability, and biocompatibility were evaluated by FTIR spectroscopy, water contact angle measurements, broth microdilution method, time-killing kinetic assays, quartz crystal microbalance analyses, MTT assays, and scanning electron microscopy analyses. Results: PDMS was loaded with r(P)ApoBLPro peptide which was found to be present not only in the bulk matrix of the polymer but also on its surface. ApoB-derived peptide was found to retain its antimicrobial properties once loaded into PDMS and the antimicrobial material was found to be stable upon storage at 4◦ C for a prolonged time interval. A gradual and significant release (70% of the total amount) of the peptide from PDMS was also demonstrated upon 400 min incubation and the antimicrobial material was found to be endowed with anti-adhesive properties and with the ability to prevent biofilm attachment. Furthermore, PDMS loaded with r(P)ApoBLPro peptide was found not to affect the viability of eukaryotic cells. Conclusions: an easy procedure to functionalize PDMS with r(P)ApoBLPro peptide has been here developed and the obtained functionalized material has been found to be stable, antimicrobial, and biocompatible

Physicochemical and antimicrobial properties of whey protein-based films functionalized with palestinian Satureja capitata essential oil

The present study aimed to produce bio-active packaging materials made of whey proteins (WPs) and essential oil (EO) extracted from Thymbra (Satureja capitata, L.), one of the most popular Palestinian wild plants. In this study, two different Thymbra leaves from Nablus and Qabatiya in Palestine were collected and analyzed for EOs by gas chromatography and mass spectrometry. Based on the analysis, two EOs, namely, TEO1 and TEO2, were extracted, and it was found that both samples primarily contain γ-terpinene and carvacrol, whereas p-cymene was detected only in TEO1. The antimicrobial activity of TEO1 and TEO2 was evaluated by microbroth microdilution assays against pathogenic bacteria and yeast. Based on the results, TEO1 exhibited potent antimicrobial activity against the test strains. Besides, TEO1 was chosen to functionalize WP-based films at different concentrations (0.1%, 0.4%, and 0.8% v/v of Film Forming Solutions). Film mechanical property investigation showed a marked reduction in the tensile strength and Young’s modulus at 0.8% TEO1. In contrast, its elongation at break value was significantly (p < 0.05) increased due to the plasticizing effect of the EO. Moreover, the film transparency was found to be significantly (p < 0.05) reduced by increasing TEO1 concentrations. Finally, microbiological investigations indicated that film antimicrobial activity against both gram-positive and gram-negative bacteria increased dose-dependently. The overall results open interesting perspectives for employing these films as preservative materials in food packaging

Ballroom Music Spillover into a Beluga Whale Aquarium Exhibit

It is not uncommon for modern aquaria to be built with special entertainment areas. There are no known measurements of sound spillover from such entertainment areas into underwater animal exhibits. Entertainment organizations typically prefer to play music for events at 95 and 100 dBA in a ballroom at Georgia Aquarium. Concern over the potential effects of the music and noise on animals in adjacent exhibits inspired an initial project to monitor and compare sound levels in the adjacent underwater exhibits against the typical in-air sound levels of the ballroom. Measured underwater noise levels were compared to modeled levels based on finite element analysis and plane wave transmission loss calculations through the acrylic viewing window. Results were compared with the model to determine how, if at all, the ambient noise level in the Cold Water Quest exhibit changed as a result of music played in the ballroom

Micromegas for imaging hadronic calorimetry

The recent progress in R&D of the Micromegas detectors for hadronic calorimetry including new engineering-technical solutions, electronics development, and accompanying simulation studies with emphasis on the comparison of the physics performance of the analog and digital readout is described. The developed prototypes are with 2 bit digital readout to exploit the Micromegas proportional mode and thus improve the calorimeter linearity. In addition, measurements of detection efficiency, hit multiplicity, and energy shower profiles obtained during the exposure of small size prototypes to radioactive source quanta, cosmic particles and accelerator beams are reported. Eventually, the status of a large scale chamber (1{\times}1 m2) are also presented with prospective towards the construction of a 1 m3 digital calorimeter consisting of 40 such chambers.Comment: 6 pages, 9 figures, CALOR2010 conferenc