Studies of cationic amphiphilic drug catalysed membrane degradation

Imperial Users onl

Securities Class Actions Move North: A Doctrinal and Empirical Analysis of Securities Class Actions in Canada

The article explores securities class actions involving Canadian issuers since the provinces added secondary market class action provisions to their securities legislation. It examines the development of civil liability provisions, and class proceedings legislation and their effect on one another. Through analyses of the substance and framework of the statutory provisions, the article presents an empirical and comparative examination of cases involving Canadian issuers in both Canada and the United States. In addition, it explores how both the availability and pricing of director and officer insurance have been affected by the potential for secondary market class action liability. The article suggests that although overall litigation exposure for Canadian companies remains relatively low when compared to their U.S. counterparts, Canadian issuers that have listed their shares in the US. face considerable uncertainty as to the extent of their exposure to securities class actions. Through analysis of case law in both jurisdictions, the article highlights the crucial role of liability caps relating to costs in the decision of which jurisdiction to file suit

Securities Class Actions Move North: A Doctrinal and Empirical Analysis of Securities Class Actions in Canada

The article explores securities class actions involving Canadian issuers since the provinces added secondary market class action provisions to their securities legislation. It examines the development of civil liability provisions, and class proceedings legislation and their effect on one another. Through analyses of the substance and framework of the statutory provisions, the article presents an empirical and comparative examination of cases involving Canadian issuers in both Canada and the United States. In addition, it explores how both the availability and pricing of director and officer insurance have been affected by the potential for secondary market class action liability. The article suggests that although overall litigation exposure for Canadian companies remains relatively low when compared to their U.S. counterparts, Canadian issuers that have listed their shares in the U.S. face considerable uncertainty as to the extent of their exposure to securities class actions. Through analysis of case law in both jurisdictions, the article highlights the crucial role of liability caps relating to costs in the decision of which jurisdiction to file suit

QCALT: a tile calorimeter for KLOE-2 upgrade

The upgrade of the DA$\Phi$NE machine layout requires a modification of the size and position of the inner focusing quadrupoles of KLOE-2 thus asking for the realization of two new calorimeters covering the quadrupoles area. To improve the reconstruction of $K_L\to 2\pi^0$ events with photons hitting the quadrupoles a calorimeter with high efficiency to low energy photons (20-300 MeV), time resolution of less than 1 ns and space resolution of few cm, is needed. To match these requirements, we are designing a tile calorimeter, QCALT, where each single tile is readout by mean of SiPM for a total granularity of 2400 channels. We show first tests of the different calorimeter components

DNA-functionalized gold nanoparticle assemblies for Surface Enhanced Raman Scattering

The programmable assembly of DNA strands is a promising tool for building tailored bottom-up nanostructures. Here, we present a plasmonic nanosystem obtained by the base-pairing mediated aggregation of gold nanoparticles (NPs) which are separately functionalized with two different single-stranded DNA chains. Their controlled assembly is mediated by a complementary DNA “bridge” sequence. We monitor the formation of DNA assembled NP aggregates in solution, and we study their Surface Enhanced Raman Scattering (SERS) response by comparison with the single NP constituents. We interpret the revealed SERS signatures in terms of the molecular and NP organization at the nanoscale, demonstrating that the action of the DNA bridge molecule yields regular NP aggregates with controlled interparticle distance and reproducible SERS response. In perspective, this demonstrates the potential of the present system as a stable, biocompatible, and recyclable SERS sensor

Melanoma mucoso de tabique nasal

ResumenLos melanomas mucosos son tumores raros y de mal pronóstico. Representan alrededor del 1% del total de melanomas y el 0,5% de los tumores malignos de cabeza y cuello. Cuando se localiza en las fosas nasales, produce sintomatología tardía e inespecífica como obstrucción respiratoria, epistaxis o dolor facial. El tratamiento de elección es la cirugía combinada con quimio y radioterapia. Presentamos un caso con sobrevida de 4 años y realizamos una revisión de la literatura.AbstractHead and neck mucosal melanoma is a rare entity with poor prognosis. This tumour represents less than 1% of malignant melanomas and 0.5% of head and neck malignancies. Melanomas that arise in the nasal cavity present with non-specific symptoms and have a poor prognosis. Wide local excision is the treatment of choice combined with postoperative chemoradiotherapy. We present a case with an unusual survival (4 years) and perform a review of the literature

Characterization and Performance of PADME's Cherenkov-Based Small-Angle Calorimeter

The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in Italy, will search for invisible decays of the hypothetical dark photon via the process $e^+e^-\rightarrow \gamma A'$, where the $A'$ escapes detection. The dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We report here on measurement and simulation studies of the performance of the Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting 2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of PbF$_2$ crystals and the newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns) and a single-crystal energy resolution of 5.7%/$\sqrt{E}$ with light yield of 2.07 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test Facility of LNF. We also propose the investigation of a two-PMT solution coupled to a single PbF$_2$ crystal for higher-energy applications, which has potentially attractive features.Comment: 12 pages, 19 figures. v2: added section on radiation damage studie

Steady and Stable: Numerical Investigations of Nonlinear Partial Differential Equations

Excerpt: Mathematics is a language which can describe patterns in everyday life as well as abstract concepts existing only in our minds. Patterns exist in data, functions, and sets constructed around a common theme, but the most tangible patterns are visual. Visual demonstrations can help undergraduate students connect to abstract concepts in advanced mathematical courses. The study of partial differential equations, in particular, benefits from numerical analysis and simulation

Dental pulp pluripotent-like stem cells (DPPSC), a new stem cell population with chromosomal stability and osteogenic capacity for biomaterials evaluation

Background: Biomaterials are widely used to regenerate or substitute bone tissue. In order to evaluate their potential use for clinical applications, these need to be tested and evaluated in vitro with cell culture models. Frequently, immortalized osteoblastic cell lines are used in these studies. However, their uncontrolled proliferation rate, phenotypic changes or aberrations in mitotic processes limits their use in long-term investigations. Recently, we described a new pluripotent-like subpopulation of dental pulp stem cells derived from the third molars (DPPSC) that shows genetic stability and shares some pluripotent characteristics with embryonic stem cells. In this study we aim to describe the use of DPPSC to test biomaterials, since we believe that the biomaterial cues will be more critical in order to enhance the differentiation of pluripotent stem cells. Methods: The capacity of DPPSC to differentiate into osteogenic lineage was compared with human sarcoma osteogenic cell line (SAOS-2). Collagen and titanium were used to assess the cell behavior in commonly used biomaterials. The analyses were performed by flow cytometry, alkaline phosphatase and mineralization stains, RT-PCR, immunohistochemistry, scanning electron microscopy, Western blot and enzymatic activity. Moreover, the genetic stability was evaluated and compared before and after differentiation by short-comparative genomic hybridization (sCGH). Results: DPPSC showed excellent differentiation into osteogenic lineages expressing bone-related markers similar to SAOS-2. When cells were cultured on biomaterials, DPPSC showed higher initial adhesion levels. Nevertheless, their osteogenic differentiation showed similar trend among both cell types. Interestingly, only DPPSC maintained a normal chromosomal dosage before and after differentiation on 2D monolayer and on biomaterials. Conclusions: Taken together, these results promote the use of DPPSC as a new pluripotent-like cell model to evaluate the biocompatibility and the differentiation capacity of biomaterials used in bone regeneration

Measurement of neutron detection efficiency between 22 and 174 MeV using two different kinds of Pb-scintillating fiber sampling calorimeters

We exposed a prototype of the lead-scintillating fiber KLOE calorimeter to neutron beam of 21, 46 and 174 MeV at The Svedberg Laboratory, Uppsala, to study its neutron detection efficiency. This has been found larger than what expected considering the scintillator thickness of the prototype. %To check our method, we measured also the neutron %detection efficiency of a 5 cm thick NE110 scintillator. We show preliminary measurement carried out with a different prototype with a larger lead/fiber ratio, which proves the relevance of passive material to neutron detection efficiency in this kind of calorimeters