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The development and progression of colorectal cancer (CRC) have been associated with inflammation processes that involve the overactivation of the NF-κB signalling pathway. The characterization of the NF-κB expression profile in CRC is an important topic since the suppression of NF-κB represents a potential therapeutic approach. In this study, we assessed the expression levels of 84 NF-κB-related genes in paired tumoral (T) and peritumoral (PT) tissues from 18 CRC patients and 18 normal colonic mucosae, and the expression levels of three miRNAs targeting the most dysregulated genes revealed by the case-control analysis. Comparing the gene expression profile of T and controls, 60 genes were dysregulated. The comparison of T and PT revealed 17 dysregulated genes in the tumoral tissues, with IL1B, CXCL8, IL1A, and CSF2 being the most upregulated. Notably, through a bioinformatics analysis, the differential gene expression of 11 out of the 17 genes was validated on a larger cohort of 308 CRC patients compared with 41 controls. Moreover, a decrease in the levels of RELA, NOD1, CASP8, BCL2L1, ELK1, and IKBKB was identified in poorly differentiated tumours compared to moderately differentiated tumours. The analysis of the three miRNAs targeting IL1B, CXCL8, IL1A, and CSF2 showed that miR-182-5p was upregulated in T compared with PT, whereas miR-10b-5p was downregulated in T compared with PT and control tissues. Our results may contribute to the design of new experimental therapeutic strategies based on endogenous molecules, such as miRNAs, to target the genetic key players of the NF- κB pathway.

Aims Allograft rejection following heart transplantation (HTx) is a serious complication even in the era of modern immunosuppressive regimens and causes up to a third of early deaths after HTx. Allograft rejection is mediated by a cascade of immune mechanisms leading to acute cellular rejection (ACR) and/or antibody‐mediated rejection (AMR). The gold standard for monitoring allograft rejection is invasive endomyocardial biopsy that exposes patients to complications. Little is known about the potential of circulating miRNAs as biomarkers to detect cardiac allograft rejection. We here present a systematic analysis of circulating miRNAs as biomarkers and predictors for allograft rejection after HTx using next‐generation small RNA sequencing. Methods and results We used next‐generation small RNA sequencing to investigate circulating miRNAs among HTx recipients (10 healthy controls, 10 heart failure patients, 13 ACR, and 10 AMR). MiRNA profiling was performed at different time points before, during, and after resolution of the rejection episode. We found three miRNAs with significantly increased serum levels in patients with biopsy‐proven cardiac rejection when compared with patients without rejection: hsa‐miR‐139‐5p, hsa‐miR‐151a‐5p, and hsa‐miR‐186‐5p. We identified miRNAs that may serve as potential predictors for the subsequent development of ACR: hsa‐miR‐29c‐3p (ACR) and hsa‐miR‐486‐5p (AMR). Overall, hsa‐miR‐486‐5p was most strongly associated with acute rejection episodes. Conclusions Monitoring cardiac allograft rejection using circulating miRNAs might represent an alternative strategy to invasive endomyocardial biopsy.

INTRODUCTION: Recent studies have suggested a higher recurrence rate of hepatocellular carcinoma (HCC) in patients with a history of HCC and hepatitis C virus (HCV)-associated cirrhosis treated with direct-acting antiviral (DAA) agents. MATERIAL AND METHODS: We conducted a prospective analysis of 24 patients with HCV-associated cirrhosis and treated HCC who received ombitasvir/paritaprevir/ritonavir+dasabuvir+ribavirin for 12 weeks. Prior therapies for HCC included resection (9/24 patients), radiofrequency ablation (RFA) (7/24) and trans-arterial chemoembolization (TACE) (8/24). All patients were eligible for treatment if they had no HCC recurrence 6 months after their last procedure. A control group was defined. All patients were followed every 6 months, with dynamic computed tomography and/or magnetic resonance imaging. RESULTS: The sustained virological response rate per protocol was 21/24 (87.5%). The study group included 14 (59%) males, median age 64 years (51–77), 50% with associated non-alcoholic steatohepatitis and 24% with Child–Pugh A6 points. HCC recurrence rate/100 patient-years was lower in the DAA-HCC group versus control: 5.5 versus 24.6% patient-years for the resection+RFA group (p = 0.044), respectively, and 18.6 versus 72.7% patient-years for TACE group (p = 0.002). Survival without recurrence was higher in the resection+RFA group (45 compared to 18 months (p

Donor organ shortage results in significant waiting list mortality. Donor lung assessment is currently based on donors' history, gas exchange, chest X-ray, bronchoscopy findings, and ultimately in situ inspection but remains subjective. We correlated histopathology and radiology in nontransplanted donor lungs with the clinical indications to decline the offered organ. Sixty-two donor lungs, not used for transplantation (2010-2019), were procured, air-inflated, frozen, scanned with computed tomography, systematically sampled, and histologically and radiologically assessed. Thirty-nine (63%) lungs were declined for allograft-related reasons. In 13/39 (33%) lungs, histology could not confirm the reason for decline, in an additional 8/39 (21%) lungs, histologic abnormalities were only considered mild. In 16/39 (41%) lungs, radiology could not confirm the reason for decline. Twenty-three (37%) donor lungs were not transplanted due to extrapulmonary causes, of which three (13%) lungs displayed severe histologic abnormalities (pneumonia, n = 2; emphysema, n = 1), in addition to mild emphysema in 9 (39%) lungs and minor bronchopneumonia in 1 (4%). Radiology revealed ground-glass opacities in 8/23 (35%) and emphysema in 4/23 (17%) lungs. Histopathologic and radiologic assessment of nontransplanted donor lungs revealed substantial discrepancy with the clinical reason for decline. Optimization of donor lung assessment is necessary to improve current organ acceptance rates. ispartof: AMERICAN JOURNAL OF TRANSPLANTATION vol:20 issue:6 pages:1712-1719 ispartof: location:United States status: published

To enhance their longevity, dental implants must be highly biocompatible and must have a low elastic modulus close to that of the bone. They must also possess a high superficial hardness and a high corrosion resistance. For these reasons, a recently developed low-modulus Ti-27Nb alloy with nontoxic elements was treated by gas nitriding at high temperature in this study. A very thin nitrided layer of 0.5 μm in thickness followed by an enriched nitrogen zone was observed. Consequently, a very high hardness evaluated at about 1800 HV was obtained in surface, which represents an increase of 4-5 times the hardness of the non-nitrided alloy. This superficial hardness was experimentally observed to decrease up to 800 nm in depth from the surface to the core. The low modulus of Ti-27Nb (evaluated at 55 GPa, which is twice lower than the commercially pure titanium) was not affected by the surface nitriding treatment. A better corrosion resistance was observed and a significant decrease in ion release rates for the nitrided alloy (ion release of 1.41 ng/cm2 compared to the 163.58 ng/cm2 obtained for the commercially pure titanium at pH = 7.48 in artificial Carter-Brugirard saliva). The cytocompatibility was not compromised and the cell viability performed on human osteoblasts, fibroblastic cells, and epithelial cells was enhanced on the nitrided surface in comparison with the non-nitrided surface. These combined properties make the nitrided Ti-27Nb alloy a good candidate for dental implant applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1483-1490, 2019.

Electrochemical aptasensors appear as promising tools in food analysis, able to provide sensitive, fast and cost-effective analysis, with the added advantage of portability. Carbon nanomaterials and in particular carbon nanotubes and graphene are among the nanomaterials most often used to build electrochemical aptasensors due to their good electrical conductivity, large surface area and multiple functionalisation possibilities. This review aims to give an overview of the types of carbon nanomaterials and their composites which have been used to enhance the performance of electrochemical aptasensors. Examples are detailed for the biosensors which were tested with real food samples. In these aptasensors, carbon nanomaterials have played different roles, from facilitating the immobilization of high amounts of aptamer and enhancing the electroactive area of the sensors to roles as nanocarrier for signaling probes in amplification schemes or even as electroactive probes generating the output signal. The survey of recent literature shows a positive evolution towards increased aptasensor testing with food samples. However, many challenges remain related to the better characterization of nanomaterials used, clarifying the roles of specific components in multi-component nanocomposites and widening the types of food matrices and analytes tested with the aptasensors. Although we are still far from knowing when these novel tools will replace classic analytical methods in food analysis, carbon nanomaterials will certainly continue to play an important role in the design of future electrochemical aptasensors for food analysis.

In this paper, the microstructure, mechanical and anticorrosive properties of the new CoCrNbMoZr alloy were studied in comparison with those of the commercial CoCrMo, Heraenium CE alloy. SEM and XRD techniques were used to evince the microstructure, and the morphology of the two alloys. Electrochemical linear and potentiodynamic polarisation and electrochemical impedance spectroscopy methods showed the electrochemical and corrosion behaviour of the alloys in artificial Carter-Brugirard saliva of different composition (doped with NaF, pH = 8.21 and undoped) and pH values (3.83; 7.84; 9.11) simulating the various functional conditions from the oral cavity. The new CoCrNbMoZr alloy showed self-passivation, more favourable values of the corrosion, passivation and transpassive potentials and tendency to passivation than those of the commercial Heraenium CE alloy and lower values of the passive current density; the values of the corrosion current densities and corrosion rates are lower and polarisation resistances are higher comparing with those of the reference alloy. EIS spectra revealed a passive film, a compact, resistant layer formed especially by the chromium, cobalt, niobium and zirconium oxides. Taking into consideration the microstructural features, electrochemical behaviour, corrosion resistance, and mechanical characteristics, it results that the new CoCrNbMoZr alloy is recommended for the dental applications.

The new Ti-15Ta-5Zr alloy revealed a homogeneous bi-phase α + β microstructure without inclusions or secondary phases. The alloy native passive film contains both Ti2O3, and TiO2 oxides and very resistant Ta2O5 and ZrO2 oxides (X-ray photoelectron spectroscopy). All main electrochemical and corrosion parameters in artificial Carter-Brugirard saliva had more favourable values than those of Ti and other implant alloys, due to the Ta and Zr alloying elements, which contributed with their protective oxides to the native passive film and due to the alloy very homogeneous microstructure. Impedance spectra indicated a passive film formed by two layers: an inner, insulating, barrier layer that provides the high corrosion resistance and an outer, porous, less protective layer that permits the absorption of ions and species from surrounding environment into its pores, favouring both interaction and bioactivity. X-ray photoelectron spectroscopy and scanning electron microscopy detected new depositions (Na3PO4 and K3PO4 protective compounds) of 5 nm thickness on the alloy surface after 1000 h in Carter-Brugirard saliva, which confer to the substrate both corrosion resistance and bioactivity.

We report a 10-year-old girl presenting with severe neonatal hypertrophic cardiomyopathy (HCM), feeding difficulties, mildly abnormal facial features, and progressive skeletal muscle symptoms but with normal cognitive development. Targeted oligonucleotide-selective sequencing of 101 cardiomyopathy genes revealed the genetic diagnosis, and the mutation was verified by Sanger sequencing in the patient and her parents. To offer insights into the potential mechanism of patient mutation, protein structural analysis was performed using the resolved structure of human activated HRAS protein with bound GTP analogue (PDB id 5P21) in Discovery Studio 4.5 (Dassault Systemes Biovia, San Diego, CA). The patient with hypertrophic cardiomyopathy and normal cognitive development was diagnosed with an HRAS mutation c.173C>T (p.T58I), a milder variant of Costello syndrome affecting a highly conserved amino acid, threonine 58. Our analysis suggests that the p.G12 mutations slow GTP hydrolysis rendering HRAS unresponsive to GTPase activating proteins, and resulting in permanently active state. The p.T58I mutation likely affects binding of guanidine-nucleotide-exchange factors, thereby promoting the active state but also allowing for slow inactivation. Patients with the HRAS mutation c.173C>T (p.T58I) might go undiagnosed because of the milder phenotype compared with other mutations causing Costello syndrome. We expand the clinical and molecular picture of the rare HRAS mutation by reporting the first case in Europe and the fourth case in the literature. Our protein structure analysis offers insights into the mechanism of the mildly activating p.T58I mutation. © 2016 Wiley Periodicals, Inc.

Background This study aims to evaluate the immediate outcomes of robotic and open gastrectomy for patients with locally advanced gastric adenocarcinomas. Methods A retrospective analysis was performed on patients undergoing curative intent gastrectomies between 2004 and 2013 in our department. Operative and postoperative outcomes as well as long-term survival data were analysed. Results Two groups of patients were analysed: the robotic group (n = 18) and the open surgery group (n = 29). Operating time in the robotic group (320.833 ± 85.186 min) was significantly longer (p = 0.0004) as compared with the open group (243.366 ± 57.973 min). The number of retrieved lymph nodes was not statistically different between the two groups (p = 0.108) and neither was the rate of postoperative complications (p = 0.294). Conclusions Robotic gastrectomy is a safe procedure, with satisfactory short- and long-term outcomes in locally advanced gastric cancer. Studies on a larger number of patients are necessary in order to confirm whether an immediate benefit in survival exists due to robotic surgery. Copyright © 2015 John Wiley & Sons, Ltd.

Summary Several atomic force microscopy (AFM) tests have been carried out on both smooth (polyimide) and rough (polyurethane) surfaces so that to obtain the best results; subsequently, the optimization of experiments performed is presented. A special emphasis has been put on the effect of tip geometry, image pre-processing procedure, scanning area, resolution, pixel size, and cantilever oscillation amplitude in tapping mode, as well as on the quality of the topographical images and 3D surface texture parameters. After viewing the scanning tip and finding out its sharpness, degradation, and contamination, a simultaneous calibration in X, Y, and Z directions, lateral calibration of SPM scanners and detection of lateral non-linearity, hysteresis, creep, and cross-coupling effects has been made. We have established the following experimental parameters: proper scanning resolution (512 × 512 pixels), adequate pixel size (between 2.9 and 19.5 nm) and suitable intermittent contact region (moderate tapping) for which the AFM images present good contrast and resolution. Using these parameters, the values of 3D texture parameters remain constant. These kinds of measurements are extremely important to conduct further AFM experiments on polyimide and polyurethane surfaces under optimal conditions, thus avoiding unwanted artifacts on the morphological images or unrealistic values for the 3D surface texture parameters that might occur. SCANNING 37:335–349, 2015. © 2015 Wiley Periodicals, Inc.

A new Ti-20Nb-10Zr-5Ta bioalloy with low Young's modulus (59 GPa) was coated with nanocrystalline hydroxyapatite (HA) ceramic layer by chemical method of soaking in a slightly supersaturated calcium and phosphate ions solution. The formation of HA was demonstrated using XRD, Raman microscopy and energy-dispersive X-ray spectroscopy; the coating morphology and microstructure were determined using SEM. The coating protective capacity and its long-term (2000 h) stability in simulated biofluids were revealed by the improvement of the all electrochemical parameters; also, HA ceramic coating reduced the alloy corrosion and ion release rates. After 2000 immersion hours in biofluids no compositional change occurs in the HA ceramic coating, only depositions from solution take place that change the coating morphology. Also, the in time increase of the coating stability and thickness (as a result of the new deposition from physiological solutions) indicates bioactivity.

In the present work, nitrogen ion implantation (original method) to enhance the corrosion performance and cytocompatibility of biomedical pure titanium (CP Ti) and Ti–6Al–4V alloy has been studied. Different characterization methods were used to investigate the corrosion resistance of the nitrided Ti and Ti–6Al– 4V samples such as anodic polarization, electrochemical impedance spectroscopy, monitoring of the open circuit potentials and corresponding gradients, evaluation of corrosion rates. Further, cell viability, initial cell spreading and osteoblast proliferation were tested in order to assess cytocompatibility of modified Ti and Ti–6Al–4V alloy. In severe functional conditions, the main electrochemical parameters for nitrided biomaterials presented better values, revealing nobler behaviour than un-nitrided samples; these more favourable values assure a very good corrosion resistance for long term of the treated biomaterials. The results of biological performance evaluation indicated that nitrided Ti and Ti–6Al–4V represent suitable biomaterials for the adhesion and proliferation of human osteoblastsin vitro. All these findings demonstrate that nitrided biomaterials exhibited a very good improvement of their corrosion resistance and biocompatibility, characteristics which recommend them as potential candidates for bone implants.

In this work, a new ternary Ti–25Ta–5Zr alloy (with nontoxic alloying elements) was obtained and used to develop a thermo-mechanical procedure in order to optimize the balance strength – elastic modulus. Data about structural (by SEM) and mechanical properties are investigated. Also, its electrochemical behaviour in Ringer–Brown and Ringer solutions of different pH values (simulating severe functional conditions of an implant) was studied by cyclic potentiodynamic and linear polarization and electrochemical impedance spectroscopy (EIS). From cyclic potentiodynamic polarization curves it resulted the nobler behaviour of the thermo-mechanical treated alloy than as-cast alloy due to the favourable influence of the applied processing. Impedance spectra were fitted with one time constant equivalent circuit characterizing a very stable, resistant oxide passive film. The values of the open circuit potentials for the treated alloy are nobler than of the as-cast alloy and tended to more positive values in time, proving that the passive film on its surface is more compact and thickened in time.

The properties of the surface films formed on Ti and its Ti–5Al–4V and Ti–6Al–3.5Fe alloys by chemical (immersion in 10 M NaOH) and thermal treatment (500 °C) were studied in this paper. Their corrosion behaviour in Ringer solution was investigated. After treatments, the sample microhardness was measured. Also, the sample surfaces were observed by an optical microscope before and after immersion in Ringer solutions. The electrochemical behaviour of the surface films obtained by the chemical and thermal treatments was studied using the methods of the electrochemical impedance spectroscopy (EIS) and monitoring of open circuit potentials at different immersion periods (up to 60 days) in Ringer solution. Microhardness increased with the increasing loads for the studied materials, showing the existence of a compact protective layer. Microscopic observations exhibited more compact coatings after 60 days of exposure in Ringer solution, due to the formation of an apatite layer. EIS spectra revealed surface films with two layers: an inner, barrier protective layer and an outer, porous apatite layer. The impedance increases in time denoting that the films have grown by apatite nucleation. Also, EIS spectra showed that the complex treatment by chemical + heat method is the most efficiently. For the samples treated by the two processes (chemical + heat) the values of the open circuit potentials are nobler than of the chemical treated samples, denoting better protective, bioactive films.

A new Ti-6Al-2Nb-1Ta alloy was obtained for to satisfy the mechanical and anticorrosion requirements in neutral corrosive environment. The corrosion behaviour of this new Ti-6Al-2Nb-1Ta alloy in 0.1 M Na2SO4, 3% NaCl solutions and synthetic sea water was studied in this paper, using potentiodynamic and linear polarisation method, electrochemical impedance spectroscopy (EIS) and monitoring of the open circuit potentials. The structure of the alloy represents an α + β uniform structure with un-oriented grains. From the potentiodynamic polarisation curves it resulted that the studied alloy is self-passivated in all three solutions having a very good and very easy tendency to passivation. The most favourable values of the electrochemical parameters were registered in 0.1 M Na2SO4 solution due to its reduced corrosivity. EIS measurements proved the improvement of the passive layer resistance with the immersion time. An electric equivalent circuit with two time constants was fitted. The values of the polarisation resistances showed very good protective capacities which improved in time. The open circuit potentials have the general tendency to ennoble in time, suggesting the thickening of the passive films and the increase of their protective capacities.

In this study, a new Ti-25Ta-25Nb (mass%) β alloy was synthesised by cold crucible semi-levitation melting. After melting, each ingot was solution treated in the β-phase domain and water quenched in order to obtain a fully recrystallised homogeneous β-phase microstructure. To evaluate the bio-corrosion property of this new alloy, corrosion tests (cyclic potentiodynamic and linear polarisation, EIS) and surface analysis (SEM) were carried out in Ringer solution at different pH values (acid, neutral and basic). The results indicated that the corrosion resistance of the Ti-25Ta-25Nb alloy is quite higher than that of the commercially pure CP Ti alloy. These results show that this new alloy possesses all the characteristics necessary for its long-term use as medical implants.

A new implant Ti–7Al–3V–2Mo–2Fe alloy was elaborated and its behaviour in Ringer–Brown and Ringer solutions (of different pH values) was studied using cyclic potentiodynamic and linear polarisation, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) with its link energy dispersive X-ray system (EDX). Cyclic potentiodynamic polarisation curves revealed that the Ti–7Al–3V–2Mo–2Fe alloy is self-passivated in Ringer solutions. Pitting corrosion appeared in alkaline Ringer solution but at very electropositive values of the breakdown and pitting protection potentials and it isnotpossibletodeveloplocal corrosionon thisalloy,eveninextremefunctional conditions. EIS spectra at open circuit potential exhibited two phase angles characterising a resistant passive film and some charge transfer reactions. SEM–EDX analysis shows the presence of some aggregates containing complex compounds of calcium, magnesium, phosphor, silicon deposited on the alloy surface.

An assay based on the electrochemical detection of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) for the evaluation of the total antioxidant capacity (TAC) was optimized. The assay is interchangeable with the classic spectrophotometric tests for TAC based on the same radical. In addition, it can be used for the analysis of dilute samples with low antioxidant capacities. A good linear correlation (R2=0.97) was obtained between the results obtained with the proposed electrochemical assay and the Trolox Equivalent Antioxidant Capacity test based on ABTS radical. The assay was successfully used to evaluate the antioxidant capacity of two red wines obtained by six different maceration-fermentation techniques.

In this paper, we applied on the surface of the new Ti%20Nb%10Zr%5Ta alloy nano-crystalline hydroxyapatite (HA) coating by the method of the chemical deposition in a solution supersaturated with Ca2+ and inline image ions. The composition and crystallinity of the obtained coating was determined by X-ray diffraction, micro-Raman, infrared, and energy dispersive X-ray spectroscopies and its morphology and porosity by scanning electron microscopy. The coating long-term corrosion behavior for 3000 soaking hours in simulated human fluids (Ringer's solutions of different pH values) was studied by cyclic potentiodynamic and linear polarization, electrochemical impedance spectroscopy and monitoring of the open circuit potentials and corresponding open circuit potential gradient due to the pH non-uniformity of the biofluid. Also, the coating biocompatibility was performed by cells (human osteoblast % HOS and human immortalized pulmonary fibroblast % Wi-38) adhesion and proliferation testing in the HA coated bioalloy extract compared to respective effects of the un-coated bioalloy extract. The initial HA nano-coating promoted the deposition of new HA layers, thickening itself and showing its ability to induce the formation of this main inorganic component of the human bone, therefore denoting bioactivity of the HA nano-coated alloy.

The mechanical properties of Ti6Al7Nb alloy deformed and heat treated at elevated temperatures were correlated with its microstructure and corrosion behaviour in Ringer (of different pH values: 2.49, 6.9 and 8.9) and Ringer–Brown solutions. Microstructural analysis revealed a Widmanstatten structure for the alloys deformed at 1100 °C (β field) and structure with α grains at 930 °C (α + β field). The thermo-mechanical processing improved the electrochemical behaviour of Ti6Al7Nb alloys, especially their passive state. Open circuit potential variations in time reflected more compact, stable, resistant passive films on the surface of the treated alloys. Open circuit potential gradients simulating the non-uniformities of pH along the implant surface have very low values that cannot generate galvanic corrosion. Corrosion rates and ion release are very much reduced. Impedance spectra were fitted with a two time-constants equivalent circuit for some alloys and with three time-constants equivalent circuit for other alloys.

The properties of the anodic oxide films formed on titanium and its implant alloys Ti-5Al-4V and Ti-6Al-4Fe are investigated in this paper. Anodic oxide films were prepared by electrochemical treatment in 3M sulphuric acid solution at 60 V for 1 min, followed by a thermal treatment consisting of heating at 500 °C for 24 h and then cooling in water. Electrochemical impedance spectroscopy (EIS) measurements were carried out at open circuit potential. Nyquist and Bode spectra exhibit a two-time constant system, attesting an oxide with two layers: a barrier inner oxide and a porous outer one. All spectra change in time, indicating a thickening of the films. Open circuit potentials were monitored (long-term, 25,000 exposure hours) in Ringer 2 solution of different pH values (6.98, 4.35, 2.5) for titanium, Ti5Al-4V and Ti-6Al-4Fe alloy but without treatment with the purpose to compare the biomaterial behaviour. It was pointed out some variations of the open circuit potentials around electropositive values, suggesting slow dissolution, re-passivation or adsorption processes.

Long-term monitoring (for 8000 exposure hours) of titanium and its implant alloys (Ti-5Al-4V, Ti-6Al-4Fe) interactions with Ringer's solutions of different pH-values (2.5, 4.35, 6.98), simulating various conditions that can appear at the contact between implant and tissues was carried out in this paper. All data were statistics treated using Medcalc program. In vitro electrochemical behaviour of titanium and its alloys reveals their self-passivation in Ringer's solutions. Monitoring of the open circuit potentials with time and pH have shown that the passive films on the implant materials studied were very stable for all tested periods. Interactions due to the non-uniformity of the physiological electrolyte pH can not produce any form of local corrosion. The tested materials present low corrosion rates which attest their very good stability for 8000 exposure hours in simulated biological environment. Surface topography characterisation using atomic force microscopy (AFM) data, correlated with the electrochemical parameters, were arguments for the stability of the samples in studied bioliquids. In vitro Beurteilung und Kontrolle von Titanimplantatwerkstoffen – Wechselwirkungen mit der physiologischen Umgebung In der vorliegenden Arbeit wurden Langzeitversuche (fur 8000 Stunden Auslagerung) zur Wechselwirkung von Titan und seinen Implantatlegierungen (Ti5Al-4V9, Ti-6Al-4Fe) mit Ringerlosungen unterschiedlicher pH-Werte (2,5, 4,35, 6,98), die verschiedene Bedingungen beim Kontakt zwischen Implantat und Gewebe simulieren, durchgefuhrt. Alle Daten wurden statistisch mit dem Medcalc-Programm behandelt. Das elektrochemische Verhalten von Titan und seinen Legierungen in vitro zeigte eine Selbstpassivierung in den Ringerlosungen. Die Kontrolle des Potentials bei offenem Stromkreis in Abhangigkeit von der Zeit und dem pH-Wert ergab, dass die Passivfilme an den untersuchten Werkstoffen wahrend der gesamten Versuchszeit sehr stabil waren. Wechselwirkungen infolge Ungleichmasigkeiten des pH-Wertes des physiologischen Elektrolyten konnten keine Form von lokaler Korrosion hervorrufen. Die untersuchten Werkstoffe wiesen geringe Korrosionsgeschwindigkeiten auf, was ihre sehr gute Stabilitat uber 8000 Stunden in der simulierten biologischen Umgebung belegt. Die oberflachentopographische Charakterisierung mittels Atomkraftmikroskopie, korreliert mit den elektrochemischen Parametern, bestatigte die Stabilitat der Proben in den untersuchten Bioflussigkeiten.

In this paper, we applied the potentiostatic anodisation method on the new Ti–20Nb–10Zr–5Ta alloy surface with the aim to increase its stability and bioactivity. The morphology (SEM) and composition (Raman, FT-IR) of the obtained anodisation nanolayer are studied. Also, electrochemical stability (by cyclic potentiodynamic polarisation and EIS), corrosion resistance (by linear polarisation), long-term behaviour (by monitoring of the open circuit potentials and corresponding open circuit potential gradients) and the characterisation of the layers deposited on the alloy surface after 1000 h in acid, neutral and alkaline Ringer and neutral Ringer–Brown solutions are presented. By potentiostatic anodisation, on the alloy surface was electrodeposited a continuous nanolayer containing TiO2 rutile type oxide. The anodised layer possesses better protective properties and at the same time better porosity, therefore a higher stability and bioactivity in comparison with the native passive film. After 1000 h in the testing solutions promoted the deposition of the brushite, phosphatotitanate and hydroxyapatite, precursors, respectively component of the human bone, namely this layer is bioactive.

A new ternary Ti–15Zr–5Nb alloy was elaborated with the aim to satisfy the most stringent requirements of a good implant material. The alloy has α + β bi-phase microstructure (by XRD and optical microscopy) and presents a proper combination between Young's modulus, elasticity and good ultimate tensile strength and 0.2% yield strength (from stress–strain tensile curve), indicating a good suitability as implant material. Electrochemical behaviour in artificial Carter-Brugirard saliva of different pH values (3.96, 7.84, and 9.11) and composition (un-doped and doped with 0.05 M NaF) that simulate the severe functional conditions in the oral cavity was evaluated. All electrochemical parameters of the new alloy revealed more favourable values than those of the CP Ti and Ti–6Al–4V ELI alloy, showing a more compact, resistant passive film formed on the new alloy surface. The corrosion rates and corresponding ion release rates for the new Ti–15Zr–5Nb alloy exhibited very low values (hundreds of times smaller) in comparison with similar commercial biomaterials. Electrochemical impedance spectra distinguished bi-layered passive film formed by inner, barrier layer and outer, porous layer. X-ray photoelectron spectra and scanning electron microscopy (SEM) observations proved that in time, protective compounds were deposited from saliva on the alloy surface, enhancing its corrosion resistance.

A new quaternary Ti–20Nb–10Zr–5Ta alloy was thermo-mechanically processed; applying a stress of 10 ton-forces after heat treatment at 1000 °C it resulted a very homogeneous, fine microstructure characterized by the best mechanical properties: low Young's modulus (60 GPa) and high tensile strength and hardness. The corrosion behaviour of this processed alloy after long-term soaking (5000 h) in simulated human fluid (Ringer solution) was studied. SEM micrographs of as-cast and processed alloy after immersion proved that their surfaces were covered with a layer with a porous microstructure. EDX analysis detected Ca, P, and O as constituent elements of this porous layer. XPS determined the presence of the protective TiO2, Nb2O5, ZrO2, and Ta2O5 oxides and of the hydroxyapatite deposited from solution. All electrochemical parameters exhibited more favourable values for the processed alloy indicating the beneficial influence of the applied treatment. Impedance parameters revealed a nobler behaviour of the processed alloy than of the as-cast one. EIS spectra showed a passive film with two layers: a compact, inner, electronically conducting, barrier layer and an outer, porous layer.

The passivity of titanium, binary Ti-15Mo and ternary Ti-15Mo-5Al alloys in hydrochloric acid solutions was studied by potentiostatic, potentiodynamic, linear polarization and electrochemical impedance spectroscopy (EIS) techniques. The anodic passivity of binary Ti-15Mo and ternary Ti-15Mo-5Al titanium alloys differs from that of the base metal in hydrochloric acid solutions. The corrosion potentials of both alloys are nobler than of the titanium because the beneficial effect of molybdenum. The critical passivation current density for binary Ti-15Mo alloy is higher than of titanium; this fact can be explained by the instability of the constituent phases in hydrochloric acid solutions. Ternary Ti-15Mo-5Al alloy exhibits two critical passivation current densities (icr1 and icr2) with higher values than of the base metal and two critical passivation potentials (Ecr1 and Ecr2); at the first critical passivation potential (Ecr1) the porous titanium trioxide (Ti3O5) is formed and at the second critical passivation potential (Ecr2) this oxide is converted to a still higher valence oxide, the compact and protective titanium dioxide (TiO2). The dissolution current densities in the passive range of alloys are higher than of the base metal due the dissolution of the alloying elements in this potential range. The alloys are more resistant than titanium presenting lower corrosion rates. A three time constants equivalent circuit was fitted: one time constant is for the double layer capacity (Cdl) and for the passive film (Rp); another time constant is for the charge transfer reactions visualised by a constant phase element (CPE) and a resistance (R1); the third time constant is for diffusion processes through the passive film represented by a resistance (R2) and a Warburg element (W). Anodische Passivitat von verschiedenen Titanbasislegierungen in aggressiven Umgebungen Die Passivitat von Titan sowie der binaren Legierung Ti-15Mo und der ternaren Legierung Ti-15Mo-5Al wurde in Salzsaurelosungen mittels potentiostatischer, potentiodynamischer und linearer Polarisation sowie elektrochemischer Impedanzspektroskopie (EIS) untersucht. Die anodische Passivitat der binaren Ti-15Mo und der ternaren Ti-15Mo-5Al Legierungen unterscheidet sich in Salzsaurelosungen von dem reinen Titan. Die Korrosionspotentiale beider Legierungen sind edler als das des Titans aufgrund des positiven Einflusses des Molybdans. Die kritische Passivierungsstromdichte fur die binare Ti-15Mo-Legierung ist hoher als die von Titan, was durch die Instabilitat der Bestandteile in den Salzsaurelosungen erklart werden kann. Die ternare Ti-15Mo-5Al-Legierung weist zwei kritische Passivierungsstromdichten (icr1 und icr2) auf, die hoher liegen als fur das reine Metall, und zwei kritische Passivierungspotentiale (Ecr1 und Ecr2); beim ersten kritischen Passivierungspotential (Ecr1) wird das porose Titantrioxid (Ti3O5) gebildet und beim zweiten kritischen Passivierungspotential (Ecr2) wird dieses Oxid in ein Oxid mit noch hoherer Wertigkeit, das kompakte und schutzende Titandioxid (TiO2), umgewandelt. Die Auflosungsstromdichten im Passivbereich der Legierungen sind hoher als beim reinen Metall aufgrund der Auflosung der Legierungselemente in diesem Potentialbereich. Die Legierungen sind widerstandsfahiger als das Titan, was sich in niedrigeren Korrosionsgeschwindigkeiten bemerkbar macht. Ein elektrischer Aquivalentschaltkreis wurde angepasst: eine Zeitkonstante steht fur die Doppelschichtkapazitat (Cdl) und fur den Passivfilm (Rp); eine weitere Zeitkonstante steht fur die Ladungsubergangsreaktionen, die durch ein Konstantphasenelement (CPE) und einen Widerstand (R1) dargestellt werden; die dritte Zeitkonstante steht fur den Diffusionsprozess durch den Passivfilm, was durch einen Widerstand (R2) und ein Warburgelement (W) reprasentiert wird.

With the growing need for quality assessment of entire software systems in the industry, new issues are emerging. First, because most software quality metrics are defined at the level of individual software components, there is a need for aggregation methods to summarize the results at the system level. Second, because a software evaluation requires the use of different metrics, with possibly widely varying output ranges, there is a need to combine these results into a unified quality assessment. In this paper we derive, from our experience on real industrial cases and from the scientific literature, requirements for an aggregation method. We then present a solution through the Squale model for metric aggregation, a model specifically designed to address the needs of practitioners. We empirically validate the adequacy of Squale through experiments on Eclipse. Additionally, we compare the Squale model to both traditional aggregation techniques (e.g., the arithmetic mean), and to econometric inequality indices (e.g., the Gini or the Theil indices), recently applied to aggregation of software metrics. Keywords: software metrics; software quality; aggregation; inequality indices

A series of new phenothiazinyl-thiazolyl-hydrazine derivatives were synthesized by Hantzsch cyclization of 1-(10-ethyl-10H-phenothiazin-3-yl)-methylidene-thiosemicarbazide with α-halocarbonyl derivatives. Comparison between classical and microwave assisted synthesis emphasizes the great advantages induced by microwaves irradiation which afforded high reaction yields in much shorter reaction time. Structural assignments were based on spectroscopic methods (high resolution NMR, FTIR, MS). The new compounds were tested in vitro for their antiproliferative activity against tumor cell lines using spectrometric methods. Most of the compounds exhibit cytotoxicity against hepatic and colon tumor cells in a dose-dependent mode and a relationship between the structure and their biological activity was observed.

Diffusion is the main mechanism to transport substances (e.g. amino-acids and proteins) within a cell. In any biological process the number of molecules is too small to satisfy the statistical assumptions implicit in diffusion theory. As an alternative, various methods to simulate diffusion have been developed, which are rather microscopic. Consequently, the time-scale and volume simulated are forcefully restricted and the final steady-state cannot be reached. In this paper we propose a macroscopic method, based on the analogy established between diffusing particles and the free electrons moving in a resistor–capacitor (RC) circuit. The purpose of this work is to extend simulation beyond the actual limits of microscopic approaches and thus to obtain additional insight into the essential mechanism of biological systems. Analysis is performed with a publicly-released package (PSPICE). A procedure to build the electrical model and to fit its parameters is proposed. Simulation yields time-evolution of particle densities including the final steady-state and transport efficiency evaluation. Our method equally allows accounting for the presence of a crowded area in the diffusion pathway, the impact of several bursts of fabricated protein, as well as the case of transport simultaneously occurring on many directions. Several examples and a case study are provided to illustrate the effectiveness of our approach. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society