Doped calcium-aluminium-phosphate cements for biomedical applications

Calcium-aluminium-phosphate cements (CAPCs) for biomedical applications, mainly intended for applications in the dental field as non-resorbable fillers, were obtained by reacting Ca-aluminates compounds, i.e. CaO·Al(2)O(3) (CA) and CaO·2 Al(2)O(3) (CA(2)), with Al(H(2)PO(4))(3) aqueous solution. Hydroxyapatite was also introduced as a bioactive dispersed phase. Suitable elements like Sr and La were used to increase the radiopacity of the set yielded pastes towards X-ray wavelength used in clinical diagnostic radiographic equipments. La and Sr doped Ca-aluminates powders have been synthesized by solid state reaction at 1,400°C from a mixture of CaCO(3), Al(2)O(3), La(2)O(3) and SrCO(3). The characteristics of the obtained powders were analyzed and related to the starting compositions and synthesis procedures. The microstructure, setting time, radiopacity and compressive strength of the CAPCs have been investigated and discussed.

Abnormal oral mucosal light reflectance: a new clinical marker of high risk for colorectal cancer

BACKGROUND

A familial predisposition to colorectal cancer (CRC) has been clearly established, consisting of familial clustering in 15-20% and clear hereditary aetiology in 5-10% of overall CRC cases. Early identification of families and individuals at high risk is essential as intensive surveillance has been demonstrated to reduce cancer incidence and overall mortality. In the present study, the value of oral mucosal light reflectance in identifying hereditary non-polyposis colorectal cancer (HNPCC) carriers was investigated.

METHODS

Twenty members of six different genetically unrelated HNPCC kindred and 30 genetically unrelated age and sex matched healthy controls were examined. Lower gingival and vestibular oral mucosal reflectance was measured using an imaging spectrophotometer.

RESULTS

HNPCC carriers showed significantly lower values in the 590-700 nm wavelength range (p<or=0.0004). A reflectance cut off value <or=47.9% at the 700 nm wavelength discriminated between HNPCC carriers and controls, with 100% sensitivity and 100% specificity.

CONCLUSIONS

These findings may provide an additional phenotypic sign in HNPCC carriers, which could be used in first level CRC population screening programmes.

Secondary ion mass spectrometry in the characterisation of boron-based ceramics

A secondary ion mass spectrometry (SIMS) study of Zr- and Ti-based borides is reported: ZrB2 ceramic samples (with and without nickel addition) and a TiB2-Ni-B4C/Cu joint were investigated. For Zr-based samples, SIMS measurements show evidence for induced effects by the presence of nickel with regard to oxygen and hydrogen absorption and zirconia formation. In the case of the TiB2-Ni-B4C/Cu joint, the ceramic-metal interface region was analysed and the extent of Cu diffusion into the ceramic material was established. SIMS results were in agreement with previously obtained SEM-EDS data.