Anodic passivity of some titanium base alloys in aggressive environments

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 (i_cr1 and i_cr2) with higher values than of the base metal and two critical passivation potentials (E_cr1 and E_cr2); at the first critical passivation potential (E_cr1) the porous titanium trioxide (Ti₃O₅) is formed and at the second critical passivation potential (E_cr2) 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 (C_dl) and for the passive film (R_p); 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).     

Evaluation of susceptibility of hydrogen-induced cracking in micro-alloyed armour steel welds using a geometry-modified implant test

Susceptibility to hydrogen-induced cracking (HIC) was evaluated in steel welds for quenched and tempered armouring steel of 4.5 mm thickness. The welds were produced using the shielded metal arc welding process with low heat support and AWS E11018M 2.4 mm consumable. The susceptibility to HIC was evaluated by means of an implant test with modified geometry in welded joints with and without preheating being applied, using consumables in ideal stock conditions and exposed to the atmosphere. It was found that the consumable stock conditions were more relevant than preheating in regard to susceptibility to HIC.     

Mirna Expression in Glaucomatous and TGFβ2 Treated Lamina Cribrosa Cells

Glaucoma is a group of optic neuropathies that leads to irreversible vision loss. The optic nerve head (ONH) is the site of initial optic nerve damage in glaucoma. ONH-derived lamina cribrosa (LC) cells synthesize extracellular matrix (ECM) proteins; however, these cells are adversely affected in glaucoma and cause detrimental changes to the ONH. LC cells respond to mechanical strain by increasing the profibrotic cytokine transforming growth factor-beta 2 (TGFβ2) and ECM proteins. Moreover, microRNAs (miRNAs or miR) regulate ECM gene expression in different fibrotic diseases, including glaucoma. A delicate homeostatic balance between profibrotic and anti-fibrotic miRNAs may contribute to the remodeling of ONH. This study aimed to determine whether modulation of miRNAs alters the expression of ECM in human LC cells. Primary human normal and glaucoma LC cells were grown to confluency and treated with or without TGFβ2 for 24 h. Differences in expression of miRNAs were analyzed using miRNA qPCR arrays. miRNA PCR arrays showed that the miR-29 family was significantly decreased in glaucomatous LC cell strains compared to age-matched controls. TGFβ2 treatment downregulated the expression of multiple miRNAs, including miR-29c-3p, compared to controls in LC cells. LC cells transfected with miR-29c-3p mimics or inhibitors modulated collagen expression.     

A case-based approach for coordinated action selection in robot soccer

Designing coordinated robot behaviors in uncertain, dynamic, real-time, adversarial environments, such as in robot soccer, is very challenging. In this work we present a case-based reasoning approach for cooperative action selection, which relies on the storage, retrieval, and adaptation of example cases. We focus on cases of coordinated attacking passes between robots in the presence of the defending opponent robots. We present the case representation explicitly distinguishing between controllable and uncontrollable indexing features, corresponding to the positions of the team members and opponent robots, respectively. We use the symmetric properties of the domain to automatically augment the case library. We introduce a retrieval technique that weights the similarity of a situation in terms of the continuous ball positional features, the uncontrollable features, and the cost of moving the robots from the current situation to match the case controllable features. The case adaptation includes a best match between the positions of the robots in the past case and in the new situation. The robots are assigned an adapted position to which they move to maximize the match to the retrieved case. Case retrieval and reuse are achieved within the distributed team of robots through communication and sharing of own internal states and actions. We evaluate our approach, both in simulation and with real robots, in laboratory scenarios with two attacking robots versus two defending robots as well as versus a defender and a goalie. We show that we achieve the desired coordinated passing behavior, and also outperform a reactive action selection approach.     

Analysis of time-gated imaging through scattering media by a Fourier optics approach

The method of Fourier optics is applied to the problem of time-gated imaging through scattering media. Tb adapt the problem to this treatment, appropriate alterations are made: The continuous medium is replaced by a cascade of thin scatterers, and a spatial filtering process is substituted for the conventional gating processes. Closed-form solutions are derived.     

New type of two-axis magnetometer

A new simple two-axis magnetometer has been developed. based on the superposition of an amorphous ferromagnetic disc over a disc-shaped piezoelectric support. At low frequencies, this device exhibits a sensitivity of ~1.7 μV/μT when the external magnetic field is orthogonal to one of the pick-up coils     

Interactions among iron, calcium, phosphorus and magnesium in the nutritionally iron-deficient rat

We studied the development of nutritional iron deficiency 0, 10, 20, 30 and 40 days after the intake of a semisynthetic diet lacking iron (diet 0) and the possible interactions with calcium, phosphorus and magnesium in both control rats and rats after 40 days of iron deficiency. During this period, iron deficiency was found to produce stress in the rats, as evidenced by high levels of cortisol in the serum. High levels of parathyroid hormone (PTH) were also found. There was a considerable increase in the absorption of calcium, phosphorus and magnesium, but the phosphorus and magnesium balance decreased and that of calcium remained practically unchanged, although there was an increase in calcium urinary elimination. Despite the noticeable degree of bone demineralization, which was evident in the femur, serum levels of calcium, phosphorus and magnesium remained constant. The present study shows that severe nutritional ferropenic anaemia provokes significant alterations in the metabolism of calcium, phosphorus and magnesium. We conclude that these alterations should be taken into account in the treatment of this pathology, given its prevalence and the fact that it may exacerbate other pathologies, particularly those related to the metabolism of calcium and phosphorus.     

Regional, disease specific patterns of smoking-attributable mortality in 2000

Background: Smoking has been causally associated with increased mortality from several diseases, and has increased considerably in many developing countries in the past few decades. Mortality attributable to smoking in the year 2000 was estimated for adult males and females, including estimates by age and for specific diseases in 14 epidemiological subregions of the world.

Methods: Lung cancer mortality was used as an indirect marker of the accumulated hazard of smoking. Never-smoker lung cancer mortality was estimated based on the household use of coal with poor ventilation. Estimates of mortality caused by smoking were made for lung cancer, upper aerodigestive cancer, all other cancers, chronic obstructive pulmonary disease (COPD), other respiratory diseases, cardiovascular diseases, and selected other medical causes. Estimates were limited to ages 30 years and above.

Results: In 2000, an estimated 4.83 million premature deaths in the world were attributable to smoking, 2.41 million in developing countries and 2.43 million in industrialised countries. There were 3.84 million male deaths and 1.00 million female deaths attributable to smoking. 2.69 million smoking attributable deaths were between the ages of 30–69 years, and 2.14 million were 70 years of age and above. The leading causes of death from smoking in industrialised regions were cardiovascular diseases (1.02 million deaths), lung cancer (0.52 million deaths), and COPD (0.31 million deaths), and in the developing world cardiovascular diseases (0.67 million deaths), COPD (0.65 million deaths), and lung cancer (0.33 million deaths). The share of male and female deaths and younger and older adult deaths, and of various diseases in total smoking attributable deaths exhibited large inter-regional heterogeneity, especially in the developing world.

Conclusions: Smoking was an important cause of global mortality in 2000, affecting a large number of diseases. Age, sex, and disease patterns of smoking-caused mortality varied greatly across regions, due to both historical and current smoking patterns, and the presence of other risk factors that affect background mortality from specific diseases.