The aim of this paper was to optimise the manufacturing parameters of a new maraging steel alloy with 8% Cr, reduced Ni content (7%), and no Co or Mo. This alloy was developed by ArcelorMittal and its trade name is LeanSi. The alloy was produced using the selective laser melting (SLM) process. In the as-built state, the microstructure of the alloy was fully martensitic. The optimisation of the manufacturing parameters was determined via a multivariate factorial design of experiments including 12 experiments and three factors. The factors (i.e., the fabrication parameters) analysed were laser power, scanning speed, and hatch distance. The objective was to eliminate porosity and maximise density. It was concluded that, to achieve this, the laser power should be set at 250 W, the scanning speed at 1000 mm/s, and the hatch distance at 80 microns. The porosity obtained under these manufacturing parameters was 0.06 ± 0.03% with a confidence level of 95%. If these manufacturing parameters were modified, the material exhibited a defective interlayer bond with the formation of "balling" and high porosity. The tensile specimens tested in the as-built state showed plastic deformation. However, all the aged specimens showed brittle fracture behaviour, evidenced by the presence of very small micro-cavities (where the fracture energy consumed was very small) and small cleavage planes. The specimens produced with the manufacturing parameters at their optimum levels and aged at 480 °C for 2 h achieved tensile strength values that averaged 1430 MPa. The porosity of these specimens was reduced by more than 85%. Reverse austenite was detected at ageing temperatures of 540 °C upwards.
We describe the clinical, histopathologic, immunohistochemical, and molecular findings in an additional case of lipoatrophic panniculitis selectively involving the ankles in a 12-year-old boy. This idiopathic, rarely reported entity is presumed to have an autoimmune pathogenesis. Histological findings are a lipophagic lobular panniculits, that in our case featured focally increased numbers of lymphocytes rimming the adipocytes, and infiltration of vascular walls by mildly atypical lymphoid cells, raising the differential diagnosis of subcutaneous panniculitis-like T-cell lymphoma.
Connective Tissue Diseases/diagnosis , Lymphoma, T-Cell/diagnosis , Panniculitis/diagnosis , Skin Neoplasms/diagnosis , Subcutaneous Fat/pathology , Adipocytes/pathology , Ankle , Atrophy , Child , Diagnosis, Differential , Humans , Male , Panniculitis/drug therapy
El pénfigo IgA es una dermatosis ampollosa, caracterizada por la presencia de lesiones vesiculosas y pustulosas, junto con depósito de IgA en los espacios intercelulares de la epidermis superficial. Se distinguen dos tipos de pénfigo IgA: el tipo dermatosis pustulosa subcórnea y el tipo dermatosis IgA neutrofílica intraepidérmica. La dapsona es el tratamiento de elección en el pénfigo IgA, pero en ocasiones hay que añadir acitretín, colchicina, isotretinoína o corticoides sistémicos.Aportamos 2 casos de pénfigo IgA del tipo dermatosis pustulosa subcórnea (AU)
Female , Male , Middle Aged , Humans , Pemphigus/diagnosis , Immunoglobulin A , Skin Diseases, Vesiculobullous/diagnosis , Biopsy , Fluorescent Antibody Technique
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Humans , Female , Young Adult , Ichthyosis/diagnosis , Pneumothorax/complications , /adverse effects , Drainage , Risk Factors
Se presenta el caso de una niña afectada con condrodisplasia puntiforme (punctata) dominante ligada a cromosoma X (CPDX2), con importantes deformidades osteoarticulares, y cuyas lesiones cutáneas se manifestaron en forma de eritrodermia ictiosiforme, para delimitarse posteriormente en ictiosis lineal. La CPDX2, también denominada síndrome de Happle, se debe a mutaciones en el gen de la proteína ligadora de emopamil, que convierte el colesterol-8(9)-3-β-ol en lanosterol (AU)
Humans , Female , Infant , Chondrodysplasia Punctata/genetics , Ichthyosis/genetics , Genetic Diseases, X-Linked/diagnosis , Cholesterol/metabolism , Achondroplasia/diagnosis
