The Effect of Surface Processing on the Shear Strength of Cobalt-Chromium Dental Alloy and Ceramics

Porcelain fused to metal is widespread dental prosthetic restoration. The survival rate of metal-ceramic restorations depends not only on the qualifications of dentists, dental technicians but also on the adhesive strength of ceramics to a metal frame. The goal of the research is to determine the optimal parameters of the surface machining of the metal frame to increase the adhesion of metal to ceramics. Adhesion of cobalt-chromium alloy and ceramics was investigated. A profilometer and a scanning electron microscope were used to analyze the morphology. To estimate the adhesion the shear strength was measured by the method based on ASTM D1002-10. A method of surface microrelief formation of metal samples by plasma-electrolyte treatment has been developed. Regimes for plasma-electrolyte surface treatment were investigated according to current-voltage characteristics and a surface roughness parameter. The samples were subjected to different surface machining techniques such as polishing, milling, sandblasting (so-called traditional methods), and plasma-electrolyte processing. Morphology of the surface for all samples was studied and the difference in microrelief was shown. The roughness and adhesive strength were measured for samples either. As a result, the mode for plasma- electrolytic surface treatment under which the adhesive strength was increased up to 183% (compared with the traditional methods) was found.     

Visualization of antitumor treatment by means of fluorescence molecular tomography with an annexin V-Cy5.5 conjugate

In vivo imaging of treatment responses at the molecular level could have a significant impact on the speed of drug discovery and ultimately lead to personalized medicine. Strong interest has been shown in developing quantitative fluorescence-based technologies with good molecular specificity and sensitivity for noninvasive 3D imaging through tissues and whole animals. We show herein that tumor response to chemotherapy can be accurately resolved by fluorescence molecular tomography (FMT) with a phosphatidylserine-sensing fluorescent probe based on modified annexins. We observed at least a 10-fold increase of fluorochrome concentration in cyclophosphamide-sensitive tumors and a 7-fold increase of resistant tumors compared with control studies. FMT is an optical imaging technique developed to overcome limitations of commonly used planar illumination methods and demonstrates higher quantification accuracy validated by histology. It is further shown that a 3-fold variation in background absorption heterogeneity may yield 100% errors in planar imaging but only 20% error in FMT, thus confirming tomographic imaging as a preferred tool for quantitative investigations of fluorescent probes in tissues. Tomographic approaches are found essential for small-animal optical imaging and are potentially well suited for clinical drug development and monitoring.     

Validation of in vivo fluorochrome concentrations measured using fluorescence molecular tomography

Fluorescence molecular tomography (FMT) has emerged as a means of quantitatively imaging fluorescent molecular probes in three dimensions in living systems. To assess the accuracy of FMT in vivo, translucent plastic tubes containing a turbid solution with a known concentration of Cy 5.5 fluorescent dye are constructed and implanted subcutaneously in nude mice, simulating the presence of a tumor accumulating a fluorescent molecular reporter. Comparisons between measurements of fluorescent tubes made before and after implantation demonstrate that the accuracy of FMT reported for homogeneous phantoms extends to the in vivo situation. The sensitivity of FMT to background fluorescence is tested by imaging fluorescent tubes in mice injected with Cy 5.5-labeled Annexin V. For small tube fluorochrome concentrations, the presence of background fluorescence results in increases in the reconstructed concentration. This phenomenon is counteracted by applying a simple subtraction correction to the measured fluorescence data. The effects of varying tumor photon absorption are simulated by imaging fluorescent tubes with varying ink concentrations, and are found to be minor. These findings demonstrate the in vivo quantitative accuracy of fluorescence tomography, and encourage further development of this imaging modality as well as application of FMT in molecular imaging studies using fluorescent reporters.     

The role of sediments in the assessment of ecological quality of European river bodies

Member States of the EU are presently involved in the enforcement of the Directive of the Council and European Parliament 2000/60/CE, the so-called Water Framework Directive (WFD), establishing a frame for the common water policy of the Union. A major objective of the WFD is to reach within 2015 a good ecological status for all relevant surface water bodies of the Union territory. The assessment of the ecological status must be supported by the assessment of both the hydromorphological conditions of the water and its chemical status as represented by basic chemical parameters such as temperature, pH, oxygen balance and nutrients, and the presence or absence (vs environmental quality standards or natural background concentration) of specific synthetic and non-synthetic micropollutants. According to this approach, the assessment of the presence in any phase (water, sediments and biota) constituting the water body of micropollutants at concentrations below the environmental standards will guarantee the protection from toxic and ecotoxic effects on humans, animal and vegetal communities associated with the water body. In this context, the state of the art in Italy as compared to that in some non-EU states, particularly in Armenia, is discussed.     

Spontaneous intracerebral haemorrhage in patients suspected of multiple sclerosis

Two cases of spontaneous intracerebral haemorrhage in adolescent girls suspected of having multiple sclerosis are reported. Surgical evacuation of haematomas in the left thalamus and left side of the pons, respectively, was performed with excellent recovery in both cases. Some clinical and pathological aspects of small arteriovenous malformations are discussed and the pertinent literature reviewed.     

High Capacity Nanocomposite Layers Based on Nanoparticles of Carbon Materials and Ruthenium Dioxide for Potassium Sensitive Electrode

This work presents the new concept of designing ion-selective electrodes based on the use of new composite materials consisting of carbon nanomaterials and ruthenium dioxide. Using two different materials varying in microstructure and properties, we could obtain one material for the mediation layer that adopted features coming of both components. Ruthenium dioxide characterized by high electrical capacity and mixed electronic-ionic transduction and nano-metric carbon materials were reportedly proved to improve the properties of ion-selective electrodes. Initially, only the materials and then the final electrodes were tested in the scope of the presented work, using scanning and transmission electron microscope, contact angle microscope, and various electrochemical techniques, including electrochemical impedance spectroscopy and chronopotentiometry. The obtained results confirmed beneficial influence of the designed nanocomposites on the ion-selective electrodes’ properties. Nanosized structure, high capacity (characterized by the electrical capacitance value from approximately 5.5 mF for GR + RuO₂ and CB + RuO₂, up to 14 mF for NT + RuO₂) and low hydrophilicity (represented by the contact angle from 60° for GR+RuO₂, 80° for CB+RuO₂, and up to 100° for NT + RuO₂) of the mediation layer materials, allowed us to obtain water layer-free potassium-selective electrodes, characterized by rapid and stable potentiometric response in a wide range of concentrations-from 10⁻¹ to 10⁻⁶ M K⁺.     

Colonoscopy: a prospective report of complications.

Patients (N = 2,097) undergoing ambulatory office colonoscopy were followed to determine the incidence of endoscopic complications. In this group, 1,320 patients had diagnostic colonoscopy with or without biopsy; 777 patients had 2,019 polyps removed. Three of 2,097 patients (0.1%) had transient hypotension requiring i.v. fluid resuscitation and oxygen administration. All patients went home without sequelae. Acute postpolypectomy bleeding occurred in 11 of 777 patients (1%) requiring acute management; bleeding was controlled during colonoscopy in all. Postpolypectomy syndrome occurred in 9 of 777 patients (1%). All patients were treated medically. Late postpolypectomy bleeding occurred in 15 of 777 patients (2%). Perforation occurred in two of 777 patients (0.3%), at 1 and 9 days postpolypectomy. Both patients underwent surgery with uneventful recoveries. We conclude that office colonoscopy including polypectomy is safe. The overall complication rate for therapeutic ambulatory colonoscopy was 5%, with major events requiring hospitalization in 2% of patients.