Synergistic Improvement of Flame Retardancy and Mechanical Properties of Epoxy/Benzoxazine/Aluminum Trihydrate Adhesive Composites.

Epoxy resin was mixed with benzoxazine resin and an aluminum trihydrate (ATH) additive to provide flame retardancy and good mechanical properties. The ATH was modified using three different silane coupling agents and then incorporated into a 60/40 epoxy/benzoxazine mixture. The effect of blending compositions and surface modification on the flame-retardant and mechanical properties of the composites was investigated by performing UL94, tensile, and single-lap shear tests. Additional measurements were conducted including thermal stability, storage modulus, and coefficient of thermal expansion (CTE) assessments. The mixtures containing more than 40 wt% benzoxazine revealed a UL94 V-1 rating with high thermal stability and low CTE. Mechanical properties including storage modulus, and tensile and shear strength, also increased in proportion to the benzoxazine content. Upon the addition of ATH to the 60/40 epoxy/benzoxazine mixture, a V-0 rating was achieved at 20 wt% ATH. The pure epoxy passed a V-0 rating by the addition of 50 wt% ATH. The lower mechanical properties at high ATH loading could have been improved by introducing a silane coupling agent to the ATH surface. The composites containing surface-modified ATH with epoxy silane revealed about three times higher tensile strength and one and a half times higher shear strength compared to the untreated ATH. The enhanced compatibility between the surface-modified ATH and the resin was confirmed by observing the fracture surface of the composites.

Thermal and Adhesion Properties of Fluorosilicone Adhesives Following Incorporation of Magnesium Oxide and Boron Nitride of Different Sizes and Shapes.

Thermally conductive adhesives were prepared by incorporating magnesium oxide (MgO) and boron nitride (BN) into fluorosilicone resins. The effects of filler type, size, and shape on thermal conductivity and adhesion properties were analyzed. Higher thermal conductivity was achieved when larger fillers were used, but smaller ones were advantageous in terms of adhesion strength. Bimodal adhesives containing spherical MgOs with an average particle size of 120 µm and 90 µm exhibited the highest conductivity value of up to 1.82 W/mK. Filler shape was also important to improve the thermal conductivity as the filler type increased. Trimodal adhesives revealed high adhesion strength compared to unimodal and bimodal adhesives, which remained high after aging at 85 °C and 85% relative humidity for 168 h. It was found that the thermal and adhesion properties of fluorosilicone composites were strongly affected by the packing efficiency and interfacial resistance of the particles.

Characterization of complex chromosome aberrations in a recurrent meningioma combining standard cytogenetic and array comparative genomic hybridization techniques.

Meningiomas were among the first solid tumors recognized as having cytogenetic alterations. The most consistent changes reported in grade I meningiomas were monosomy 22 or partial 22q deletion. The vast majority of meningiomas are histologically benign, but the prognosis is determined by risk of recurrence after surgical treatment. Despite important advances in the identification of prognostic factors in the past decade, the exact nature of tumor recurrence remains largely unknown. In the present study, a recurrent transitional meningioma deriving from the anterior portion of the falx cerebri was characterized by combining conventional cytogenetics and array comparative genomic hybridization (CGH). Cytogenetic analysis at diagnosis revealed the following complex numerical and structural aberrations: 42,XY,der(1)t(1;?)(p12;?),-6,der(12;15)(q10;q10),-18, -22. Additional clonal evolutions were further identified with disease relapse. Array CGH corroborated the cytogenetic findings. The presence of a complex cytogenetic profile and progression-associated chromosomal abnormalities in a benign meningioma suggests the existence of underlying molecular events.

Spinal intradural extramedullary mature cystic teratoma in an adult.

Spinal intradural extramedullary teratoma is a rare condition that develops more commonly in children than in adults and may be associated with spinal dysraphism. We report a rare case of adult-onset intradural extramedullary teratoma in the thoracolumbar spinal cord with no evidence of spinal dysraphism and without the history of prior spinal surgery. The patient was a 38-year-old male whose chief complaint was urinary incontinence. X-ray images of the thoracolumbar spine showed the widening of the interpedicular distance and posterior marginal erosion of the vertebral bodies and pedicles at the T11, T12, and L1 level. Magnetic resonance imagings of the lumbar spine showed a lobulated inhomogeneous high signal intradural mass (87x29x20 mm) between T11 and L1 and a high signal fluid collection at the T11 level. Laminectomy of the T11-L1 region was performed, and the mass was subtotally excised. The resected tumor was histopathologically diagnosed as a mature cystic teratoma. The patient's symptom of urinary incontinence was improved following the surgery.