PZT films for micro-pumps

A micro-pump for medical applications is being developed using organometallic derived PZT thin films and silicon micromachining technology. Critical issues include the deposition of 'thick' PZT films (1 to 2 mu m thickness), film processing compatibility with available Si/SixNy/Ta/Pt structures and the establishing of piezoelectric poling parameters. A processing technique for the preparation of thick PZT films is presented. Piezoelectric properties are characterized by both direct method using alternating compressional force and by converse method using laser interferometry. In poled films of approximately 1.0 mu m thickness, d(33) values of about 130 pC/N were measured by both direct and converse methods. Maximum d(33) constants of approximate to 200 pC/N were measured with 8 V bias voltage. Mechanical resonance was excited in a 1 cm by 1 cm silicon substrate by a 0.8 mu m thick PZT film poled at 15 V

TUBB4A-related hypomyelinating leukodystrophy: New insights from a series of 12 patients

none18Background Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) was first described in 2002. After the recent identification of TUBB4A mutation as the genetic basis of the disease, the clinical and neuroimaging phenotype related to TUBB4A mutations expanded, ranging from primary dystonia type 4 with normal MRI to severe H-ABC cases. Patients and methods The study included patients referred to us for an unclassified hypomyelinating leukodystrophy. We selected patients with deleterious heterozygous TUBB4A mutations. Molecular analysis of TUBB4A was performed on genomic DNA extracted from peripheral blood. Results The series included 12 patients (5 females and 7 males). Five patients carried the common mutation c.745G > A (p.Asp249Asn), while the remaining harbored different mutations. Three new mutations were found in 5 patients. Clinical and neuroimaging observations are described. A clear correlation between the clinical presentation and the genotype seems to be absent in our group of 12 patients. Conclusions TUBB4A-mutated patients manifest a comparable clinical and neuroimaging picture but they can differ from each other in terms of rate of disease progression. Extrapyramidal signs can be absent in the first stages of the disease, and a careful evaluation of MRI is fundamental to obtain the final diagnosis. From a therapeutic perspective a trial with l-dopa should be considered in all patients presenting extrapyramidal symptoms.noneTonduti D.; Aiello C.; Renaldo F.; Dorboz I.; Saaman S.; Rodriguez D.; Fettah H.; Elmaleh M.; Biancheri R.; Barresi S.; Boccone L.; Orcesi S.; Pichiecchio A.; Zangaglia R.; Maurey H.; Rossi A.; Boespflug-Tanguy O.; Bertini E.Tonduti, D.; Aiello, C.; Renaldo, F.; Dorboz, I.; Saaman, S.; Rodriguez, D.; Fettah, H.; Elmaleh, M.; Biancheri, R.; Barresi, S.; Boccone, L.; Orcesi, S.; Pichiecchio, A.; Zangaglia, R.; Maurey, H.; Rossi, A.; Boespflug-Tanguy, O.; Bertini, E