A study of ionic defects in modified lead titanate ceramics

Pb_1–x Ca _x [(Co_0.5W_0.5)_0·05Ti_0.95]O₃ ceramics with x = 0.24, 0.30 and 0.35, are prepared by a solid state reaction of oxides. Deviations from nominal chemical compositions and formation of segregated phases different from modified lead titanate perovskites, are studied. Pyro- and non-pyroelectric currents excited in the material by a thermal wave are investigated and related to mobility of electrical charges in the materials.     

Characterization of modified PbTiO3 ceramic particles by statistical treatment of their size distribution

Microstructural characteristics of (Pb, Ca)TiO₃ piezoelectric ceramic particles have been deduced from computer analysis of their images and the corresponding statistical treatment of the data obtained. It is intended that this study should be used as a nexus, or link, between the geometrical parameters of these particles and some of their physical properties.     

Lipolysis,lipid peroxidation and texture of Serrano ham processed under different ripening temperature conditions

Lipolysis, lipid peroxidation, texture and rancid taste were investigated in Serrano hams processed under low, medium and high ripening temperature conditions (RTC) for 15 months. Medium RTC hams showed the highest contents of saturated and monounsaturated free fatty acids (FFAs) from month 5 to 15 and of polyunsaturated FFAs from month 7 to 12. The primary peroxidation index decreased during ripening in all hams, with higher levels for low RTC hams from month 5 onwards. Contrarily, the secondary peroxidation index increased during ripening in all hams, with higher levels for medium RTC hams from month 7 onwards. Texture parameters varied significantly among ham muscles. Shear force increased during ripening in all hams, with higher values for medium RTC hams, whereas cutting force was not influenced by RTC or ripening time. Rancid taste scarcely developed during ripening and was not affected by RTC.     

In Vivo Evaluation of Sgc8-c Aptamer as a Molecular Imaging Probe for Colon Cancer in a Mouse Xenograft Model

Recent biotechnological applications in the field of clinical oncology led to the identification of new biomarkers as molecular targets of cancer, and to broad developments in the field of personalized medicine. Aptamers are oligonucleotides (ssDNA or RNA) that are selected to specifically recognize a molecular target with high affinity and specificity. Based on this, new horizons for their use as molecular imaging probes are being explored. The objective of this work was to evaluate the Sgc8-c aptamer conjugated with Alexa Fluor 647 fluorophore as an imaging probe in a colon tumor xenograft mouse model, with potential application in molecular imaging. In this study, the LS174T cell line was used to induce colorectal adenocarcinoma in nude mice. After confirmation of PTK7 overexpression by immunohistochemistry, in vivo studies were performed. Pharmacokinetic, in vivo and ex vivo biodistribution imaging, and a competition assay were evaluated by fluorescence imaging. In vivo visualization of the probe in the tumors was assessed two hours after aptamer probe administration, exhibiting excellent tumor-to-background ratios in biodistribution studies and high specificity in the competition test. Our results demonstrated the functionality of Scg8-c as an imaging probe for colon cancer, with potential clinical applications.     

Chemical processing and microstructure of piezoelectric lead titanate ceramics

Lead titanate-based ceramics with different microstructures were prepared from PbO-TiO₂ gels with equimolar and non-equimolar mixtures of the oxides. Deviations from the initial compositions were found in the sintered materials. As a consequence, microstructures with different grain sizes and secondary phases were developed in the resultant ceramics. These microstructures had a strong influence on the piezoelectric behaviour of the materials obtained.     

Pathophysiologic role of redox status in blood platelet activation. Influence of docosahexaenoic acid

Decrease of platelet glutathione peroxidase activity results in increased life span of lipid hydroperoxides, especially the 12-lipoxygenase product of arachidonic acid, 12-HpETE. Phospholipase A₂ activity is subsequently enhanced with the release of arachidonic acid, which results in higher thromboxane formation and platelet function. Docosahexaenoic acid may either potentiate platelet lipid peroxidation or lower it when used at high or low concentrations, respectively. In the case of slowing down lipid peroxidation, docosahexaenoic acid was specifically incorporated in plasmalogen ethanolamine phospholipids. This could have a relevant pathophysiologic role in atherothrombosis.     

Resolution of moment equations in a nonlinear optical amplifier

In the letter a new method for the resolution of the moment equations in a nonlinear optical amplifier is exposed. Results for the four first moments for the saturated and unsaturated absorption cases are presented. These results are in good agreement with those obtained by other authors.     

Patch migration: a serious late complication of thoracotomy lead systems

Thoracotomy patch leads used for implantable cardioverter defibrillators (ICDs) are generally safe and effective. We describe two patients in whom a late complication of patch lead migration occurred years after the original implants, causing a bronchopleural fistula in one and lingular lobe collapse in the other patient. We conclude that patch migration is a late but possible complication of extrapericardial ICD leads, and should be suspected in patients who present with hemoptysis, atypical pneumonia, or lung collapse after the initial ICD surgery.     

Cardiovascular changes in a group of patients with heredoataxia. Clinical, electrocardiographic and echocardiographic findings

INTRODUCTION: Heredoataxias form a group of degenerative diseases of the nervous system, which are progressive and hand sound in particular families. MATERIAL AND METHODS: Between August 1994 and September 1995. 14 patients diagnosed as having heredoataxia were studied after admission to our hospital. Eight of these had Friedrich's ataxia (group A) and 6 had other types of ataxia (group B). A standard set of investigations were done, including clinical examination, laboratory tests (such as glycaemia and a lipidogram) to evaluate coronary risk factors. A 12 lead electrocardiogram and bidimensional and m mode echocardiogram were also done to detect disorders of conduction, changes in morphology and cardiac function, together with functional cardiovascular and neurological scales. The patients studied were between 14 and 41 years of age. RESULTS: The most frequent cardiovascular symptom was dyspnoea of effort. Changes on the electrocardiogram were seen in 92% of the patients, mainly from Group A (100%) and were due to alterations of ventricular repolarization and non-specific alterations of conduction and of rhythm. Echocardiogram changes were found in 42.8% of the patients, most frequently due to an increase in the myocardial mass of the left ventricle. CONCLUSIONS: Close correlation between age of onset and duration of the illness, and functional cardiovascular impairment was only seen in patients of Group A, in whom there was an earlier onset of the condition.