Limitations of Dental Panoramic Tomography in the anterior mandible

Dental Panoramic Tomography (DPT) is a widely used and valuable examination in dentistry. One area prone to artefacts and therefore misinterpretation is the anterior region of the mandible. This case study discusses a periapical radiolucency related to lower anterior teeth that is discovered to be a radiographic artefact. Possible causes of the artefact include a pronounced depression in the mental region of the mandible or superimposition of intervertebral spaces. Additional limitations of the DPT image include superimposition of radio-opaque structures, reduced image detail compared to intra-oral views and uneven magnification. These problems often make the DPT inappropriate for imaging the anterior mandible.

CLINICAL RELEVANCE: Panoramic radiography is often unsuitable for radiographic examination of the anterior mandible.

Transport of laser accelerated proton beams and isochoric heating of matter

The acceleration of intense proton and ion beams by ultra-intense lasers has matured to a point where applications in basic research and technology are being developed. Crucial for harvesting the unmatched beam parameters driven by the relativistic electron sheath is the precise control of the beam. We report on recent experiments using the PHELIX laser at GSI, the VULCAN laser at RAL and the TRIDENT laser at LANL to control and use laser accelerated proton beams for applications in high energy density research. We demonstrate efficient collimation of the proton beam using high field pulsed solenoid magnets, a prerequisite to capture and transport the beam for applications. Furthermore we report on two campaigns to use intense, short proton bunches to isochorically heat solid targets up to the warm dense matter state. The temporal profile of the proton beam allows for rapid heating of the target, much faster than the hydrodynamic response time thereby creating a strongly coupled plasma at solid density. The target parameters are then probed by X-ray Thomson scattering (XRTS) to reveal the density and temperature of the heated volume. This combination of two powerful techniques developed during the past few years allows for the generation and investigation of macroscopic samples of matter in states present in giant planets or the interior of the earth.

Measurement of The Dynamic Response of Compressed Hydrogen by Inelastic X-Ray Scattering

Measurement of the dynamic properties of hydrogen and helium under extreme pressures is a key to understanding the physics of planetary interiors. The inelastic scattering signal from statically compressed hydrogen inside diamond anvil cells at 2.8 GPa and 6.4 GPa was measured at the Diamond Light Source synchrotron facility in the UK. The first direct measurement of the local field correction to the Coulomb interactions in degenerate plasmas was obtained from spectral shifts in the scattering data and compared to predictions by the Utsumi-Ichimaru theory for degenerate electron liquids.

Bax's 'Sea Symphony'

Bax's Fourth is the only one of his symphonies that alludes explicitly to an extramusical stimulus: 'a rough sea at flood-tide on a sunny day'. This essay contextualizes Bax's frequent use of sea imagery throughout his oeuvre, noting in particular the peripherality of the composer's observation of the sea from the liminal position of the shore. It then considers how the idea of the sea in the Fourth Symphony is related to several musical features (motivic coherence, thematic expansion, formal anomalies), and how the sea is central to the underlying conflict in the work between nature and humanity.

Investigation of the solid-liquid phase transition of carbon at 150 GPa with spectrally resolved X-ray scattering

We have resolved the solid-liquid phase transition of carbon at pressures around 150GPa. High-pressure samples of different temperatures were created by laser-driven shock compression of graphite and varying the initial density from 1.30g/cm³ to 2.25g/cm³. In this way, temperatures from 5700K to 14,500K could be achieved for relatively constant pressure according to hydrodynamic simulations. From measuring the elastic X-ray scattering intensity of vanadium K-alpha radiation at 4.95keVat a scattering angle of 126°, which is very sensitive to the solid-liquid transition, we can determine whether the sample had transitioned to the fluid phase. We find that samples of initial density 1.3g/cm³ and 1.85g/cm³ are liquid in the compressed states, whereas samples close to the ideal graphite crystal density of 2.25g/cm³ remain solid, probably in a diamond-like state.

The fungal microbiota of de-novo paediatric inflammatory bowel disease

Inflammatory bowel disease (IBD) is characterised by an inappropriate chronic immune response against resident gut microbes. This may be on account of distinct changes in the gut microbiota termed as dysbiosis. The role of fungi in this altered luminal environment has been scarcely reported. We studied the fungal microbiome in de-novo paediatric IBD patients utilising next generation sequencing and compared with adult disease and normal controls. We report a distinct difference in fungal species with Ascomycota predominating in control subjects compared to Basidiomycota dominance in children with IBD, which could be as a result of altered tolerance in these patients. 

Crush responses of composite cylinder under quasi-static and dynamic loading

Despite the abundance of studies investigating the performance of composite structures under crush loading, disagreement remains in the literature regarding the effect of increased strain rate on the crush response. This study reports an experimental investigation of the behaviour of a carbon-epoxy composite energy absorber under static and dynamic loading with a strain rate of up to 100s^-1. Consistent damage modes and measured force responses were obtained in samples tested under the same strain rate. The energy absorption was found to be independent of strain rate as the total energy absorption appeared to be largely associated with fibre-dominated fracture, which is independent of strain rate within the studied range. The results from this study are beneficial for the design of energy absorbing structures.

The cost of treating severe refractory asthma in the UK: an economic analysis from the British Thoracic Society Difficult Asthma Registry

Severe refractory asthma poses a substantial burden in terms of healthcare costs but relatively little is known about the factors which drive these costs. This study uses data from the British Thoracic Society Difficult Asthma Registry (n=596) to estimate direct healthcare treatment costs from an National Health Service perspective and examines factors that explain variations in costs. Annual mean treatment costs among severe refractory asthma patients were £2912 (SD £2212) to £4217 (SD £2449). Significant predictors of costs were FEV1% predicted, location of care, maintenance oral corticosteroid treatment and body mass index. Treating individuals with severe refractory asthma presents a substantial cost to the health service.

Civilianizing Civil Conflict: Civilian Defense Militias and the Logic of Violence in Intra-State Conflict

This article examines how civilian defense militias shape violence during civil war. We define civilian defense forces as a sedentary and defensive form of pro-government militia that incumbents often use to harness the participation of civilians during a counterinsurgency campaign. We argue that civilian defense forces reduce the problem of insurgent identification. This leads to a reduction in state violence against civilians. However, we also claim that these actors undermine civilian support for insurgents, which leads to an increase in rebel violence against civilians and overall intensification of conflict. A statistical analysis of government and rebel violence against civilians from 1981 to 2005, and a qualitative assessment of a civilian defense force operating in Iraq from 2005 to 2009, offer strong support for our theoretical claims. These findings provide further insight into pro-government militias and their effects on violence. They also have wider ethical implications for the use of civilian collaborators during civil war.