Laser-Driven Proton Beams: Acceleration Mechanism, Beam Optimization, and Radiographic Applications

This paper reviews recent experimental activity in the area of optimization, control, and application of laser accelerated proton beams, carried out at the Rutherford Appleton Laboratory and the Laboratoire pour l’Utilisation des Lasers Intenses 100 TW facility in France. In particular, experiments have investigated the role of the scale length at the rear of the plasma in reducing target-normal-sheath-acceleration acceleration efficiency. Results match with recent theoretical predictions and provide information in view of the feasibility of proton fast-ignition applications. Experiments aiming to control the divergence of the proton beams have investigated the use of a laser-triggered microlens, which employs laser-driven transient electric fields in cylindrical geometry, enabling to focus the emitted
protons and select monochromatic beam lets out of the broad spectrum beam. This approach could be advantageous in view
of a variety of applications. The use of laser-driven protons as a particle probe for transient field detection has been developed and
applied to a number of experimental conditions. Recent work in this area has focused on the detection of large-scale self-generated magnetic fields in laser-produced plasmas and the investigation of fields associated to the propagation of relativistic electron both on the surface and in the bulk of targets irradiated by high-power laser pulses.

Impact of osteoarthritis and analgesic treatment on quality of life of an elderly population

To determine the quality of life of elderly patients with osteoarthritis (OA) compared with that of their peers with no chronic illnesses and to investigate the associations between analgesic use and quality of life.

Time for treating bone fracture using rhBMP-2: a randomised placebo controlled mouse fracture trial.

Although the mechanisms of osteoinduction by bone morphogenic proteins (BMPs) are increasingly understood, the most appropriate time to administer BMPs exogenously is yet to be clarified.The purpose of this study was to investigate when BMP may be administered to a fracture arena to maximise the enhancement of healing.Forty mice with externally fixed left femoral fractures were randomised into four groups: Group I, the control group was given a placebo of 30 ll saline at day 0; Groups II, III and IV were given 30 ll saline plus 2.5 lg rhBMP-2, at post-operative days 0, 4 or 8, respectively.Sequential radiographs were taken at days 0, 8, 16.On day 22 the mice were sacrificed and both femora were harvested for biomechanical assessment in 3-point bending and histological evaluation.Radiographic analysis indicated that healing of fractures in Groups II and III was significantly greater (p <0.05) than those in Groups I and IV, at both 16 and 22 days post-fracture. The highest median bone mineral content at the fracture site was evidenced in Group III and II.Furthermore, Group III also had the highest relative ultimate load values, followed by Groups II, IV and I.Greater percentage peak loads were observed between Group I and both Groups II and III (p <0.05). Histological examination confirmed that at 22 days post-fracture, only fractures in Groups II and III had united with woven bone, and Groups I and IV still had considerable amounts of fibrous tissue and cartilage at the fracture gap.Data presented herein indicates that there is a time after fracture when rhBMP administration is most effective, and this may be at the time of surgery as well as in the early fracture healing phases.

The human synovial fluid proteome: A key factor in the pathology of joint disease

This review aims to summarise our knowledge to date on the protein complement of the synovial fluid (S F). The tissues, structure and pathophysiology of the synovial joint are briefly described. The salient features of the S F proteome, how it is composed and the influence of arthritic disease are highlighted and discussed. The concentrations of proteins that have been detected and quantified in SF are drawn together from the literature on osteoarthritis, rheumatoid arthritis and juvenile idiopathic arthritis. The measurements are plotted to give a perspective on the dynamic range of protein levels within the SF. Approaches to proteomic analysis of SF to date are discussed along with their findings. From the recent literature reviewed within, it is becoming increasingly clear that analysis of the SF proteome as a whole, could deliver the most valuable differential diagnostic fingerprints of a number of arthritic disorders. Further development of proteomic platforms could characterise prognostic profiles to improve the cliniciads ability to resolve unremitting disease by existing and novel therapeutics.

TiK alpha radiography of Cu-doped plastic microshell implosions via spherically bent crystal imaging

We show that short pulse laser generated Ti K alpha radiation can be used effectively as a backlighter for radiographic imaging. This method of x-ray radiography features high temporal and spatial resolution, high signal to noise ratio, and monochromatic imaging. We present here the Ti K alpha backlit images of six-beam driven spherical implosions of thin-walled 500-mu m Cu-doped deuterated plastic (CD) shells and of similar implosions with an included hollow gold cone. These radiographic results were used to define conditions for the diagnosis of fast ignition relevant electron transport within imploded Cu-doped coned CD shells. (c) 2005 American Institute of Physics.

A method to reconstruct patient-specific proximal femur surface models from planar pre-operative radiographs

Three-dimensional reconstruction from volumetric medical images (e.g. CT, MRI) is a well-established technology used in patient-specific modelling. However, there are many cases where only 2D (planar) images may be available, e.g. if radiation dose must be limited or if retrospective data is being used from periods when 3D data was not available. This study aims to address such cases by proposing an automated method to create 3D surface models from planar radiographs. The method consists of (i) contour extraction from the radiograph using an Active Contour (Snake) algorithm, (ii) selection of a closest matching 3D model from a library of generic models, and (iii) warping the selected generic model to improve correlation with the extracted contour.

This method proved to be fully automated, rapid and robust on a given set of radiographs. Measured mean surface distance error values were low when comparing models reconstructed from matching pairs of CT scans and planar X-rays (2.57–3.74 mm) and within ranges of similar studies. Benefits of the method are that it requires a single radiographic image to perform the surface reconstruction task and it is fully automated. Mechanical simulations of loaded bone with different levels of reconstruction accuracy showed that an error in predicted strain fields grows proportionally to the error level in geometric precision. In conclusion, models generated by the proposed technique are deemed acceptable to perform realistic patient-specific simulations when 3D data sources are unavailable.

Adverse reactions to drugs: in vitro studies with isolated cells

Objective and design: Drug-induced adverse reactions can be allergic or pseudoallergic in nature, in this study the histamine releasing ability of 4 radiographic contrast media and 2 opioid analgesics was tested on a variety of mast cell containing cell suspensions.