Low-grade myofibroblastic sarcoma (LGMS) is a distinct mesenchymal myofibroblastic malignancy. The tumor may occur at a variety of sites, but is particularly associated with the head and neck. Of the two maxillary sarcomas that were analyzed in the present study, one was misdiagnosed as an inflammatory myofibroblastic tumor during pre-operative excision biopsy, and later presented with a different immunophenotype upon recurrence. Representative paraffin blocks from formalin-fixed tissues were selected from each patient and designated as case 1 and case 2. Immunohistochemical studies were performed on 3-μm thick sections using primary antibodies against α-smooth muscle actin (α-SMA), muscle-specific actin (MSA), desmin, vimentin, calponin, h-caldesmon, fibronectin, cytokeratin, cluster of differentiation 34 (CD34), S-100 protein, anaplastic lymphoma kinase (ALK), epithelial membrane antigen (EMA) and Ki-67. Immunohistochemistry was performed using the streptavidin-biotin-peroxidase complex method. The tumor cells from the two maxillary LGMSs, including the recurrent lesion, were positive for vimentin and fibronectin, and negative for S-100 protein, CD34, EMA, h-caldesmon, ALK, MSA and calponin. The tumor cells from case 1 demonstrated positive staining for α-SMA protein and negative staining for desmin. By contrast, the tumor cells from the primary lesion in case 2 presented with negative staining for α-SMA and positive staining for desmin, while the cells of the recurrent lesion were α-SMA-positive and desmin-negative. The present study concluded that cases of LGMS with immunoprofile alterations are predictive of relatively poor prognoses.

The effect of addition of nano‐sized particles on densification and thermal conductivity of AlN ceramics was investigated. The commercially available AlN powder (∼0.9 μm) was mixed with 1.89 mass% nano‐sized AlN particles (<0.1 μm), 3.53 mass% Y2O3, and 2.0 mass% CaO as sintering aid. The mixture was fired at 1500° and 1600°C in a tungsten resistance furnace under flowing N2 atmosphere. The results showed that a fully densified specimen was obtained at the lower temperature of 1600°C by addition of nano‐sized particles. The thermal conductivity of the resulting product was 133 W/m°C. The value is much higher than the 52 W/m°C for the sample prepared without adding the nano‐sized AlN powder. This study indicates a strong potential for the use of nano‐sized particles as additives in the densification of AlN ceramics.

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Nano‐sized aluminum nitride (AlN) powders can enhance the sinterability of AlN ceramics. The present work examined the pulverization and dispersion of AlN powder using ZrO2 beads of 0.1 mm in diameter as grinding medium in order to obtain nano‐sized powder for low‐temperature sintering. An attracting feature of the bead grinding is that the rotor creates centrifugal and shearing forces, which lead to efficient pulverization that exceeds the conventional grinding limit. The AlN powder with agglomerates and average particle size of 0.38 μm was broken up into more homogeneous particles with a narrow particle size distribution after 90 min of grinding. Qualitative examinations of the powder by transmission electron microscopy and BET indicated that the particle size was 50–100 nm and specific surface area was 70 m2/g.