High-pressure operation of a xenon-GPSC/MSGC hybrid detector for hard X-ray spectrometry

The performance of a high-pressure xenon gas proportional scintillation counter/microstrip gas chamber (GPSC/MSGC) hybrid detector has been investigated for filling pressures from 1 up to 10 bar, for 22-, 30- and 60-keV photons. GPSC/MSGC hybrid detectors are based on a xenon-GPSC instrumented with a CsI-coated microstrip plate photosensor placed directly within the xenon envelope, as a substitute for the photomultiplier tube. This design avoids the constraints due to the use of a quartz scintillation window for GPSC-photosensor coupling, which absorbs a significant amount of scintillation and is a drawback for applications where large detection areas and high filling pressures are needed. The lowest energy resolutions are achieved for 2 bar (5.5% and 3.4%, FWHM, for 22- and 60-keV photons, respectively). Increasing the pressure to the 5-6 bar range, competitive energy resolutions of 7% and 4.5% are still achieved for 22- and 60-keV photons, respectively. This detector could be a compelling alternative in applications where compactness, large detection area, insensitivity to strong magnetic fields, room temperature operation, large signal-to-noise ratio and good energy resolution are important requirements.http://www.sciencedirect.com/science/article/B6TJM-4M3B6DG-8/1/04ba8b77386c4c69025c7ca19342f79

Recent advances in X-ray detection with micro-hole and strip plate detector

We report on the performance of a micro-hole and strip plate, fabricated with standard gas electron multiplier-production procedures, presenting 40-[mu]m hole-diameter and 30-[mu]m wide anode strips. Multiplication factors of 5×104 were reached in an Ar/Xe (95/5) atmosphere at about 1 bar; the energy resolution is of the order of 14% (FWHM) for 5.9-keV X-rays.http://www.sciencedirect.com/science/article/B6TJM-4BRJY00-1/1/d80a918485bf806c1feae6bbd514d4e

Evaluation of canine adipose-derived stem cells in a healthy mice subcutaneous model

Canine adipose-derived stem cells (cASCs) have great interest for cell-based therapies in Veterinary Medicine. As the behaviour of these cells in non-autologous recipients is not deeply characterized, it is mandatory to study them in new animal models previously to canine specie. In this work, cASCs were injected subcutaneously in mice and these cells were detected by immunohistochemistry using vimentin, CD44 and keratin. The local response evaluated by histology did not reveal signals of significant inflammatory reaction neither in the lymph nodes or other organs. This study showed the implantation of cASCs induced a scarce inflammatory response. Hsd:CD1 (ICR) mouse can be proposed as an animal model to study the in vivo behavior of the cASCs and to validate new cASCs-based approaches avoiding or reducing the use of dogs in research

GEM scintillation readout with avalanche photodiodes

The use of the scintillation produced in the charge avalanches in GEM holes as signal amplification and readout is investigated for xenon. A VUV-sensitive avalanche photodiode has been used as photosensor. Detector gains of about 4 × 104 are achieved in scintillation readout mode, for GEM voltages of 490 V and for a photosensor gain of 150. Those gains are more than one order of magnitude larger than what is obtained using charge readout. In addition, the energy resolutions achieved with the scintillation readout are lower than those achieved with charge readout. The GEM scintillation yield in xenon was measured as a function of GEM voltage, presenting values that are about a half of those achieved for the charge yield, and reach about 730 photons per primary electron at GEM voltages of 490 V

Micro-hole and strip plate-based photosensor

The performance of a new VUV photosensor, based on an micro-hole and strip plate (MHSP) electron multiplier with a CsI photocathode deposited on its top electrode, is described. This photosensor presents gains above 104 when operating in an Ar-5%Xe gas mixture at 1 atm. Although the gain of a single MHSP is not sufficient for efficient detection of single photons, this simple UV photosensor may be useful for the detection of higher light levels, such as primary- and secondary scintillation in noble gases.http://www.sciencedirect.com/science/article/B6TJM-4NRK4D4-D/1/18d650609693fd3de3e82b0afa66396

First Report of <i>Kocuria kristinae</i> in the Skin of a Cuban Boa (<i>Epicrates angulifer</i>)

During a routine clinical examination of a four-year-old female Cuban boa (Epicrates angulifer) belonging to a zoological park located in northern Portugal, a skin lesion was observed. A skin swab was taken. Bacteriological analysis conducted using the Vitek® 2 Compact system identified the presence of the bacteria species Kocuria kristinae, a new bacterial pathogen that may be a potential pathogen in wild animals. This K. kristinae strain was resistant to kanamycin, pradofloxacin, erythromycin, clindamycin, tetracycline, nitrofurantoin, and trimethoprim/sulphamethoxazole and was therefore classified as a multidrug-resistant bacterium. To the authors’ knowledge, this is the first time that K. kristinae has been described in the skin of a Cuban boa. This report serves as a cautionary warning about the importance of recognising and investigating the potential pathogenicity of this agent, as well as contributing to the development of strategies to prevent the spread of antibiotic-resistant microorganisms

Periodontal tissue engineering strategies based on nonoral stem cells

Periodontal disease is an inflammatory disease which constitutes an important health problem in humans due to its enormous prevalence and life threatening implications on systemic health. Routine standard periodontal treatments include gingival flaps, root planning, application of growth/differentiation factors or filler materials and guided tissue regeneration. However, these treatments have come short on achieving regeneration ad integrum of the periodontium, mainly due to the presence of tissues from different embryonic origins and their complex interactions along the regenerative process. Tissue engineering (TE) aims to regenerate damaged tissue by providing the repair site with a suitable scaffold seeded with sufficient undifferentiated cells and, thus, constitutes a valuable alternative to current therapies for the treatment of periodontal defects. Stem cells from oral and dental origin are known to have potential to regenerate these tissues. Nevertheless, harvesting cells from these sites implies a significant local tissue morbidity and low cell yield, as compared to other anatomical sources of adult multipotent stem cells. This manuscript reviews studies describing the use of non-oral stem cells in tissue engineering strategies, highlighting the importance and potential of these alternative stem cells sources in the development of advanced therapies for periodontal regeneration.Grant sponsor: Joao Filipe Requicha PhD Scholarship; Grant number: SFRH/BD/44143/2008; Grant sponsor: Portuguese Foundation for Science and Technology (FCT)

Solid Modelling in Haskell

We investigate the suitability of the functional model of programming as applied to the solid modelling field of 3D rendering, with particular reference to expressiveness and efficiency. We find that functional languages with a good implementation can be more efficient than other languages in certain aspects in the rendering process. Furthermore, recent developments in functional languages allow difficult concepts to be expressed simply within programs, and allow easier expression of the models we wish to render. 1 Introduction A currently popular area of computing research is functional languages. These are inspired by mathematical notation, and the work of the mathematicians Haskell B. Curry and Alonzo Church. These languages claim to be mathematically pure, which helps program manipulation and proofs. At the same time, a graphics technique known generally as Constructive Solid Geometry is gaining favour, especially now it has been enlivened with new raytracing and texture-mapping m..