Search results for "Solid"

Synthesis and biological properties of the seven alanine-modified analogues of the marine cyclopeptide hymenamide C

2002

The synthesis and biological activity of the marine cyclopeptide hymenamide C(1), showing an inhibitory effect on human neutrophil elastase degranulation release, were recently described. Based on this result, it was decided to undertake a systematic structure-activity relationship study of this cyclopeptide, based on the Ala-scan technique, in order to obtain useful information for the rational design of additional analogues. The synthesis and characterization of the seven Ala modified analogues are reported and their biological and pharmacological properties are described.

Conditioning following powder micronization: influence on particle growth of salbutamol sulfate.

2003

Micronization is a high-energy process that induces changes in the crystallinity of materials. As a result, the crystalline structures on the particles' surface are being destroyed and amorphous areas are formed. After micronization of salbutamol sulfate to be used in dry powder inhalers, only small amounts of amorphous material are produced. Nevertheless, even these small amounts can have important effects on the physical stability of the powder. The amorphous state is thermodynamically unstable and tends to convert to the stable, crystalline state. The recrystallization process of disordered regions on the particles' surface leads to particle growth of milled particles. In this case, brid…

Adenosine and memory storage

1999

Rationale: Caffeine is a non-selective A1/A2 adenosine receptor antagonist which is known to improve cognitive performance in humans. This effect of caffeine has been attributed to its antagonism of adenosine receptors. Objective: The present study was devised to identify the role of A1 and A2A adenosine receptors in the facilitation of memory consolidation in mice performing a passive avoidance task. Methods: Adult albino Swiss male mice were used. The mice were trained in a step-through inhibitory avoidance task in which they were punished by a foot-shock (0.4 mA, 5 Hz, for 3 s) delivered through the grid floor. Caffeine (0.1, 0.3, 1.0 and 3.0 mg/kg), SCH 58261 (0.1, 0.3, 1.0 and 3.0 mg/k…

Cover Picture: Synthesis and Biological Evaluation of a Multiantigenic Tn/TF-Containing Glycopeptide Mimic of the Tumor-Related MUC1 Glycoprotein (Ch…

2006

Bone metabolism in children with asthma treated with nebulized flunisolide: a multicenter italian study

1998

Abstract This multicenter, parallel-group, open-label, randomized study was conducted in prepubertal children with mild asthma to investigate the efficacy and influence on bone and collagen turnover of a daily regimen of flunisolide 1200 μg alone (group A, n=14), flunisolide 600 μg in combination with sodium cromoglycate (SCG) 60 mg (group B, n=15), or SCG 60 mg alone (group C, n=15) for 4 months. All medications were administered by means of a jet nebulizer using a mouthpiece. Serum osteocalcin (OC), bone alkaline phosphate (B-ALP), and procollagen type I carboxyterminal propeptide (PICP) were measured as markers of bone formation, and type I collagen telopeptide (ICTP) was measured as a m…

Dielectric Properties of PbSc1/2Nb1/2O3-PbTiO3Ceramics

2004

Lead titanate solid solutions exhibits extreme values of some physical parameters. We have investigated a ferroelectric relaxor ceramics of PSN-PT composition near the morphotropic phase boundary. Results are discussed with account for the relaxor properties related to defects and disordering of the PSN-PT system.

Low and Infra-Low Frequency Measurements in Lead Titanate Solid Solutions

2006

The study of PSN-PT ferroelectric relaxor ceramics exhibiting extreme values of some physical parameters near the morphotropic phase boundary is reported. The results are discussed to account for the relaxor properties related to defects and disordering of the PSN-PT system.

Effects of structure ordering, structure defects and external conditions on properties of complex ferroelectric perovskites

1998

Abstract Structural rearrangements in lead-containing (A‘A’) (B’B“)O3 type perovskite compounds are caused by technological treatment, high-energy radiation and ambient conditions. Variation of structure ordering along with modification (substituted or defected solid solutions) may provide promising compositions for applications, e.g., cascade microcryogenic devices (PST solid solutions); efficient piezoelectric materials – here the new (1 – x)Pb(Lu1/2Nb1/2)O3 – xPbTiO3 system in the morphotropic region. The maximum values of the electromechanical coupling coefficients kp = 0·663, kt = 0·481, k 31 = 0·355 were attained in compositions PLuNT 59/41 (Tm = 353°C) near the morphotropic phase bou…

Ceramics and Thin Films of Some New Pb(B 3+ ,Nb)TiO 3 -PbTiO 3 Systems

2003

The structure, dielectric, and electromechanical properties of (1 m x )Pb(B 3+ ,Nb)TiO 3 - x PbTiO 3 binary systems (B = Lu, Er, Tb, Ho) are reported. The crystallographic features at the morphotropic phase boundary (MPB) between tetragonal P4mm and pseudo-monoclinic M phases are discussed with respect to electro-mechanical properties. Doping effect (with La 3+ ) on the properties of ceramic samples of pseudobinary Pb(Lu 1/2 Nb 1/2 )O 3 -PbTiO 3 (PLuNT) system has been investigated. Pb(Mg 1/3 Nb 2/3 )-PbTiO 3 (PT) solid solutions were studied under different processing conditions for obtaining ceramics of 100% perovskite structure with sufficient high j T EC ∼ 1 K near room temperature. The…

Phase behaviour of binary mixtures of colloidal charged spheres

2008

Abstract As a step towards the modelling of binary metal alloys we here report on the shape of the phase boundary of two deionized charged sphere colloidal suspensions as a function of mixing ratio and particle density. Their size ratios are r = 0.68 and r = 0.56. Both aqueous suspensions of polystyrene copolymer spheres crystallize in a body-centred cubic structure. Interesting differences in the shape of the phase boundary are observed. In the first case a peaked increase of crystal stability was observed for a mixing ratio of p = 0.2–0.3, which gives the fraction of small spheres. Also in the second case the stability of the crystalline phase is larger than expected for an ideal solid so…