Cu(II) and Zn(II) complexes with hyaluronic acid and its sulphated derivative.Effect on the motility of vascular endothelial cells.

With the aim of improving the compatibility of biomaterials to be used for the construction of cardiovascular prosthesis, we have designed bioactive macromolecules resulting from chemical modifications of hyaluronic acid (Hyal). The stability constants of Cu(II) and Zn(II) complexes with the sulphated derivative of hyaluronic acid (HyalS3.5) were evaluated. Two different complexes have been found for each metal ion, CuL, Cu(OH)2L and ZnL, Zn(OH)2L (L means the disaccharide unit of the ligands) in aqueous solution at 37 degrees C. The dihydroxo Cu(II) complex was present in high percentage at pH=7.4. On the contrary, the Zn(II) ion was present with a relatively low percentage of both complexes. The ability to stimulate endothelial cell adhesion and migration was evaluated for Hyal, HyalS3.5 and their complexes with Cu(II) and Zn(II) ions. The results revealed that Hyal and [Cu(OH)2HyalS3.5](4.5)- induced cell adhesion, while [ZnHyalS3.5](2.5)- and [Zn(OH)2HyalS3.5](4.5)- inhibited the process. The chemotactic activity of increasing concentrations of the above complexes was also evaluated, demonstrating that [Cu(OH)2HyalS3.5](4.5)- complex at 1 microM concentration was the most active in inducing cell migration. These results have been also strengthened by analysing adherent cell migration in agarose. In conclusion, sulphated hyaluronic acid coordinated to Cu(II) seems to be a promising matrix molecule for the construction of cardiovascular prosthesis.

Low-threshold heterogeneously integrated InP/SOI lasers with a double adiabatic taper coupler

We report on a heterogeneously integrated InP/silicon-on-insulator (SOI) laser source realized through divinylsiloxane-bis-benzocyclobutene (DVS-BCB) wafer bonding. The hybrid lasers present several new features. The III-V waveguide has a width of only 1.7 mu m, reducing the power consumption of the device. The silicon waveguide thickness is 400 nm, compatible with high-performance modulator designs and allowing efficient coupling to a standard 220-nm high index contrast silicon waveguide layer. In order to make the mode coupling efficient, both the III-V waveguide and silicon waveguide are tapered, with a tip width for the III-V waveguide of around 800 nm. These new features lead to good laser performance: a lasing threshold as low as 30 mA and an output power of more than 4 mW at room temperature in continuous-wave operation regime. Continuous wave lasing up to 70 degrees C is obtained

Integration of high performance silicon optical modulators

We present our recent work on high speed silicon optical modulators developed within the UK silicon photonics and HELIOS projects. Examples of their integration with other photonic and electronic elements are also presented

Prevalence of dementia in Tuscany: results from four population-based epidemiological studies

OBJECTIVE: to provide information on epidemiology of dementia in Tuscany needed to plan for dedicated health and social services. DESIGN: analysis of pooled baseline data from 4 population-based longitudinal studies. SETTING: 4 municipalities in Tuscany. PARTICIPANTS: 4,056 elderly subjects enrolled in 4 longitudinal studies. MAIN OUTCOME MEASURES: age- and sex-specific dementia prevalence rates and estimated number of demented people, by degree of cognitive impairment and BADL disability in the elderly population of Tuscany. RESULTS: out of the evaluated subjects, 293 are demented. Prevalence of dementia increases from about 1 % in the 65-69 age group to about 28 % in the 90+ age group both among women and men. About 43% of the demented study subjects suffer from severe mental deterioration (MMSE < 14) and56% are disabled in at least one Basic Activity of Daily Living (BADL). We estimate that about 19 thousand demented elderly men and 40 thousand demented elderly women are currently living in Tuscany of whom 26 thousand severely mentally impaired and 34 thousand disabled in at least one BADL. The resulting overall dementia prevalence standardised on the Italian 65+ population is 5,3% for men and 7,7% for women. CONCLUSIONS: these estimates could be used as a basis for the evaluation and the planning of social and health care services dedicated to demented people