Microfabricated Lamb wave device based on PZT sol-gel thin film formechanical transport of solid particles and liquids

The fabrication using silicon micromachining and characterization of an acoustic Lamb wave actuator is presented. The intended use of the device is for mass transport and sensor applications. The device consists of dual interdigitated transducers patterned on a thin-film composite membrane of silicon nitride, platinum, and a sol-gel-derived piezoelectric ceramic (PZT) thin film. The acoustic properties of the device are presented along with preliminary applications to mechanical transport and liquid delivery systems. Improved acoustic signals and improved mass transport are achieved with PZT over present Lamb wave devices utilizing ZnO or AlN as the piezoelectric transducer     

Influence of structure on the antioxidant activity of indolinic nitroxide radicals

An in vitro study was carried out to verify whether the chain length of a substituent on an indolinic nitroxide could influence its antioxidant activity in different biological environments subjected to oxidative stress. Three distinct indolinic nitroxides were synthesized and compared with vitamin E and Trolox (a hydrophilic analogue of vitamin E), where the only difference between the nitroxides was the length of the hydrocarbon chain in the 2-position of indole, namely 2 (C2), 10 (C10), and 18 (C18) carbons. All the nitroxides were effective in preventing oxidation of bovine serum albumin, but to different extents, with the longer chain derivatives being more efficient. However, the C2 compound was the most efficient in preventing lipid peroxidation in microsomal membranes. The C2 and C18 compounds, Trolox, and vitamin E protected microsomal protein oxidation to the same extent at the highest concentration used (13 microM). The nitroxide with a C10 chain was less effective in this system. The influence of these compounds on the enzymatic activity of two mitochondrial proteins subjected to oxidative stress was also studied by means of oxygraph measurements. Mitochondrial rotenone-sensitive NADH oxidase and succinate oxidase responded differently to BuOOH-induced radical chemistry, and the compounds under study also protected the activity of the two enzymes but to different extents. The results clearly demonstrate that indolinic nitroxides are very efficient antioxidants, protecting both lipids and proteins from peroxidation. The indole structure influences the antioxidant efficacy in biological systems.     

Solution for M/G/1 queues

M/G/1 type queueing systems are frequently found in the performance evaluation of communication systems. The authors develop a new solution method for these queues: their results are an alternative to both standard forms of exact analysis, and to diffusion approximations, while offering comparable computational complexity to the latter     

Anatomically constrained electrical impedance tomography forthree-dimensional anisotropic bodies

As shown previously for two-dimensional geometries, anisotropy effects should not be ignored in electrical impedance tomography (EIT) and structural information is important for the reconstruction of anisotropic conductivities. Here, we describe the static reconstruction of an anisotropic conductivity distribution for the more realistic three-dimensional (3-D) case. Boundaries between different conductivity regions are anatomically constrained using magnetic resonance imaging (MRI) data. The values of the conductivities are then determined using gradient-type-algorithms in a nonlinear-indirect approach. At each iteration, the forward problem is solved by the finite element method. The approach is used to reconstruct the 3-D conductivity profile of a canine torso. Both computational performance and simulated reconstruction results are presented together with a detailed study on the sensitivity of the prediction error with respect to different parameters. In particular, the use of an intracavity catheter to better extract interior conductivities is demonstrated     

DNA sequence dependent binding modes of bis(vinylpyridinium)benzene derivatives

The DNA binding selectivity of new dicationic ligands based on the bis(vinylpyridinium)benzene unit has been investigated by means of UV-Vis absorption spectroscopy. From the experimental results it is concluded that these extended pi-electron bridged viologens have relatively high affinity to AT base pair sequences whereas the binding to GC pairs is about 10 times lower, and binding affinity depends on minor variation in the ligand structure. Linear type ligand exhibits two binding mode interaction, intercalation at high dye concentration which undergoes switching to groove binding at low ligand concentration.     

Comorbidity of drug dependence and other mental disorders: a two-phase study of prevalence at outpatient treatment centres in Italy

The proposed mechanism of action of the antineoplastic drug 3-nitrobenzothiazolo[3,2-alpha]quinolinium chloride (NBQ-2) involves its interaction with DNA by intercalation and inhibition of topoisomerase II activity by arresting the enzyme in a covalent cleavage complex. In an attempt to identify some structural determinants for activity and develop a molecular structure/cytotoxicity correlation, four new structural analogs of the antitumor NBQ-2 were prepared and their cytotoxic activity and DNA binding properties were investigated. The cytotoxic activity was evaluated against six different human tumor cell lines: U937, K-562, HL-60, HT-29, HeLa, and A431. The results showed that these new drugs elicit pronounced cytotoxic effects against U937, K-562, HL-60 and A431 while HeLa and HT-29 were less sensitive to the new drugs. This apparent selectivity was different to that of m-AMSA, a drug currently used for cancer treatment. Since the interaction of NBQ-2 to DNA by intercalation has been proposed as the initial step leading to its antineoplastic activity, DNA binding and changes in DNA contour length induced by the new NBQ-2 structural analogs were also investigated using calf thymus and human DNA. The drug, 7-(1-propenyl)-3-nitrobenzimidazolo[3,2-alpha]quinolinium chloride (NBQ-59) was the most cytotoxic agent of the analog series (IC50 = 16 microM for HL-60 cells), however, it demonstrated the weakest binding to DNA (Kint = 0.9 x 10[5] M-1 for calf thymus DNA). NBQ-59 was also found to be a poor intercalator into the DNA double helix. Therefore, our results suggest that DNA binding is not the primary mechanism of drug action for this family of compounds. In addition structural determinants important for cytotoxicity of the benzazolo quinolinium chlorides were suggested by our results. In particular, the nitro group in the 3 position does not seem to be necessary for bioactivity, while substitutions in the benzazolo moiety have striking effects on the biological activity of the drugs.     

Use of cell ELISA for the screening of neurotrophic activities on minor cell populations in retinal monolayer cultures

BACKGROUND: Whereas the secretion of the male vesicular gland in most mammals is amorphous, that of the tree shrew, Tupaia glis, was observed to be stored as globules. METHODS: Vesicular and prostate glands from Tupaia, fixed in glutaraldehyde and osmium, were studied in the light and electron microscopes. Other materials considered included the Tupaia ejaculate produced by electroejaculation and, for comparative purposes, sections of the vesicular gland from a dermopteran, the flying lemur. RESULTS: The vesicular gland epithelium in Tupaia secretes small granular aggregates and occasionally a denser aggregate that is associated with cells having obvious apical Golgi lamellae. In the alveolar lumen, these aggregates unite with others to form, respectively, granular and some dense globules of up to approximately 15 mu in diameter, which appear as such in semen produced by electroejaculation. In contrast to the prostate, however, precursor secretion vesicles were rare in the vesicular epithelium. Although poorly fixed, the vesicular gland secretion from a flying lemur also appeared to form globules. CONCLUSIONS: Although it is unlike the homogeneous secretion elaborated in most mammals, including primates and insectivores, the globular product of the Tupaia vesicular gland seems comparable to that in a variety of mega- and microbats, among representative species of which it appears to provide the bulk material for the vaginal copulation plug. Because a museum specimen examined here also indicates its occurrence in a flying lemur, the globular vesicular gland secretion common to Tupaiidae, to at least some Mega- and Microchiroptera, and apparently to Dermoptera may provide a soft tissue feature of some value in the cladistic approach to phylogenetic reconstruction within the Archonta. Anat.