Eruptive disseminated superficial porokeratosis with rapid resolution: a drug-induced phenomenon?

We report a case of eruptive disseminated superficial porokeratosis occurring in a 63-year-old man with no history of excessive sun exposure. Unlike disseminated superficial actinic porokeratosis, this condition resolved rapidly with minimal topical treatment. This is most likely to have represented a drug-induced phenomenon, which is very rarely reported in the dermatological literature.

Study of dynamic grain growth by electron microscopy and EBSD.

The effect of hot deformation on fully recrystallized aluminium-copper alloys (Al-4wt%Cu and Al-33wt%Cu) with different volume fractions of CuAl(2) has been studied. The alloys are Zener pinned systems with different superplastic properties. Strain-induced grain growth, observed in both alloys, was quantitatively estimated by means of electron microscopy and EBSD and compared with the rate of static grain growth. Surface marker observations and in situ hot-deformation experiments combined with EBSD were aimed at clarifying the mechanisms responsible for the changes in the deformed microstructures. A sequence of secondary and backscattered electron images and EBSD maps was obtained during in situ SEM deformation with different testing conditions. Overlaying EBSD maps for the Al-4wt%Cu with channelling contrast images showed that grain boundary motion occurred during deformation, creating a layered structure and leading to an increase in size of some grains and shrinkage of others. Of a particular interest are results related to behaviour of CuAl(2) in superplastic Al-33wt%Cu during deformation, including several problems with the use of EBSD in this alloy.

The influence of low-strain thermo-mechanical processing on grain boundary network characteristics in type 304 austenitic stainless steel.

Grain boundary engineering of austenitic stainless steel, through the introduction of plastic strain and thermal annealing, can be used to develop microstructures with improved resistance to inter-granular degradation. The influence of low-strain thermo-mechanical processing on grain boundary network development, with systematic variations of annealing treatments, has been investigated. Three stages of the microstructure development during grain boundary engineering in low-strain processing conditions are identified, and correlated with changes in grain boundary character and deviation distributions. Low-energy connected length segments at triple junctions, which have been proposed to be responsible for crack bridging during inter-granular stress corrosion cracking, can be influenced by the choice of the annealing treatment parameters. The development of individual grain boundary length segments of different character showed consistent trends with increasing grain size. Crack length predictions are consistent with the beneficial effect of designing microstructures with high fractions of twin grain boundaries and smaller grain size.

Recrystallization phenomena in an IF steel observed by in situ EBSD experiments.

In situ electron backscatter diffraction microstructural analysis of recrystallizing interstitial free steels deformed to strains of 0.75 and 1.6 has been carried out in a FEG-SEM. The experimental procedures are discussed, and it is shown that there is no degradation of the electron backscatter diffraction patterns at temperatures up to 800 degrees C. Analysis of the surface and interior microstructures of annealed samples shows only minor difference, which suggests that in situ annealing experiments are of value. In addition, it is shown that in situ measurements allow a detailed comparison between the same areas before and after annealing, thereby providing information about the recrystallization mechanisms. Sequential recrystallization phenomena, such as initiation and growth of new grains, are observed at temperatures over 740 degrees C, and depending on the deformation histories, different recrystallization behaviour is observed. It is found that {111} <123> recrystallized grains are preferentially formed in the highly deformed material, whereas no strong recrystallization texture is formed in the lower strained material.

Guidelines for evaluation and management of urticaria in adults and children.

Appropriate management of urticaria depends on the correct evaluation of clinical patterns and causes where these can be identified. Guidance for treatment is presented, based on the strength of evidence available at the time of preparation. As many of the recommendations relate to the off-licence use of drugs, it is particularly important that clinicians should be familiar with dosing and side-effects of treatment in the context of managing urticaria.

The characterization of low-angle boundaries by EBSD.

A method of accurately measuring misorientations by electron backscatter diffraction (EBSD), which is an extension of that proposed by Wilkinson and based on the comparison of diffraction patterns, is described. The method has been applied to linescans, and found to improve the angular resolution by a factor of more than 30. The consequent improvement in determining misorientation axes is also analysed. Small changes of orientation very close to some low-angle boundaries were investigated and found to be artefacts of the analysis. Measurements of the area from which diffraction patterns are generated show this to be much larger than the effective spatial resolution of EBSD, and it is concluded that this may be a limiting factor in the use of EBSD for microstructural characterization.

Randomized, double-blind, placebo-controlled pilot study to assess the value of free radical scavengers in reducing inflammation induced by cryotherapy.

The inflammation which follows cryotherapy is a significant disadvantage of this therapeutic modality. To date, the only treatment shown to reduce this inflammation is application of topical corticoids. We have therefore conducted a pilot study to investigate whether pretreatment with the free radical scavengers, vitamins C and E might alleviate the signs and symptoms of inflammation following liquid nitrogen cryotherapy of common warts. We undertook a randomized, double-blind, placebo-controlled, parallel group study. We recruited 40 adult patients, of whom 38 returned for evaluation. Treatments comprised vitamin C (2000 mg) and vitamin E (800 IU) daily or matching placebo for 7 days prior to cryotherapy to a hand wart. Oedema volume, erythema level, pain intensity and the presence or absence of blistering were assessed 24 h after cryotherapy. There were no significant differences between the two treatment groups in any of the parameters assessed. This study yielded no suggestion of benefit from the use of pretreatment with free radical scavengers in conjunction with liquid nitrogen cryotherapy.

A study of recrystallization in single-phase aluminium using in-situ annealing in the scanning electron microscope.

In-situ annealing experiments were performed in the scanning electron microscope on a single-phase Al-0.13Mg alloy cold rolled to different strain levels. Once the validity of the technique had been verified by comparison of the recrystallization kinetics and final grain size with bulk annealed samples, the method was used in combination with electron back-scattered diffraction (EBSD) to study the potential mechanisms for recrystallization in this alloy. During annealing of material rolled to moderate strains (epsilont < 0.7), the primary mechanism was strain-induced boundary migration (SIBM). In material rolled to higher true strains (epsilont > 1.4), recrystallization occurred extensively along pre-existing cube bands and EBSD measurements showed that the mean size of cells within the cube bands was larger than for all other orientations measured, suggesting a size advantage was responsible for the strengthening of cube texture during recrystallization. SIBM was shown to occur concurrently with the nucleation along cube bands but this contributed a lower proportion of nucleation sites during recrystallization.

Quantifying recrystallization by electron backscatter diffraction.

The use of high-resolution electron backscatter diffraction in the scanning electron microscope to quantify the volume fraction of recrystallization and the recrystallization kinetics is discussed. Monitoring the changes of high-angle grain boundary (HAGB) content during annealing is shown to be a reliable method of determining the volume fraction of recrystallization during discontinuous recrystallization, where a large increase in the percentage of high-angle boundaries occurs during annealing. The results are shown to be consistent with the standard methods of studying recrystallization, such as quantitative metallography and hardness testing. Application of the method to a highly deformed material has shown that it can be used to identify the transition from discontinuous to continuous recrystallization during which there is no significant change in the percentage of HAGB during annealing.

Reconstruction of grains and subgrains from electron backscatter diffraction maps.

Electron backscatter diffraction maps are capable of yielding a substantial amount of quantitative information about grains, subgrains and boundaries, and the amount and quality of the data may be substantially increased if the pixels of the map are re-analysed so as to 'reconstruct' complete grains or subgrains. The paper discusses the various methods of grain reconstruction and the use of such methods to obtain microstructural information correlating the parameters of dimension, position, orientation and misorientation, which cannot usually be obtained by other means. Grain reconstruction also reveals the nature, location and contacts of all the triple junctions in the microstructure, and the paper discusses two important examples of how these data may be further analysed using automated routines. Boundary connectivity and the length and direction of likely paths along which grain boundary events such as creep fracture or stress corrosion may occur can readily be determined. The overall alignment of boundaries in deformed metals, with respect to the crystallography and the deformation geometry, may be determined as a function of the length and misorientation of the boundary segments.

The application of a hot deformation SEM stage, backscattered electron imaging and EBSD to the study of thermomechanical processing.

The technique of combining in situ hot-deformation and high resolution electron backscattered diffraction (EBSD) has been applied to study the mechanisms operating during the thermomechanical processing of metals. A simple hot tensile-straining stage is installed in a field emission gun scanning electron microscope equipped with an EBSD system and has been used successfully for a number of preliminary investigations. These investigations include substructure formation, dynamic subgrain and grain growth, superplastic deformation in aluminium alloys, and dynamic recrystallization in copper. Despite the surface topography, which inevitably increases during plastic deformation, channelling contrast backscattered electron micrographs have been successfully obtained after strains of up to approximately 50%. Good quality EBSD maps have been obtained after strains of up to 100%. Most observations and measurements from the in situ experiments are consistent with what is known about the mechanisms occurring in the bulk. The microstructures revealed in the centre of the in situ samples after later repolishing are generally similar to those at the surface.

Characterizing the deformed state in Al-0.1 Mg alloy using high-resolution electron backscattered diffraction.

The application of high resolution electron backscatter diffraction (EBSD) in a field emission gun scanning electron microscope to the characterization of a deformed aluminium alloy is discussed and the results are compared with those obtained by transmission electron microscopy. It is shown that the adequate spatial resolution, accompanied by the improvement in angular resolution to approximately 0.5 degrees that can be achieved by data processing, together with the extensive quantitative data obtainable, make EBSD a suitable method for characterizing the cell or subgrain structures in deformed aluminium. The various methods of analysing EBSD data to obtain subgrain sizes are discussed and it is concluded that absolute subgrain reconstruction is the most accurate.

Management and diagnostic guidelines for urticaria and angio-oedema.

These guidelines for management of urticaria and angio-oedema have been prepared for dermatologists on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of aetiology, diagnosis and investigation.