Challenges in the development of treatment guidelines for bipolar disorder

Bipolar disorder (BD) is such a complex mental disorder, that even the development of true, reliable, and valid treatment guidelines seems to be a goal almost impossible to achieve. The challenges include the complexity and uniqueness of the clinical picture and the therapeutical options available, special issues including gender, pregnancy, and the different views of therapists and patients. An additional issue is the method for the development of the guidelines, with systematic reviews of the hard evidence to constitute the most recent trend. The grading of the literature findings could be crucial for the whole process, as it is often ‘contaminated’ by expert opinion. Unfortunately, in the literature, BD is treated as a fragmented condition and each fragment is studied separately as if it were independent. This, in combination with incomplete reporting of the findings, makes the synthesis of the landscape almost impossible and the development of a comprehensive single algorithm for the continuous treatment of BD, extremely difficult. Overall, developing treatment guidelines for BD constitutes a great challenge. This task demands an exhaustive review of the existing literature, searching for unpublished data and digging deep into them to comprehend their nature. It also needs to manage to synthesize the fragmented research picture that refers to isolated faces of the disorder, into a comprehensive network of decision-making that will incorporate the knowledge of the past with decisions for the present by having the mind in the future (the three-fingers rule)

Application of a tribocorrosion test protocol to detect the surface state behaviour of AlCuFeCr and AlMg complex metallic alloys

edition: Biotribology - Bridging Engineering and Medicinestatus: publishe

Tribo-electrochemical characterization of metallic biomaterials for total joint replacement

Knee and hip joint replacement implants involve a sliding contact between the femoral component and the tibial or acetabular component immersed in body fluids, thus making the metallic parts susceptible to tribocorrosion. Micro-motions occur at points of fixation leading to debris and ion release by fretting corrosion. beta-Titanium alloys are potential biomaterials for joint prostheses due to their biocompatibility and compatibility with the mechanical properties of bone. The biotribocorrosion behavior of Ti-29Nb-13Ta-4.6Zr was studied in Hank's balanced salt solution at open circuit potential and at an applied potential in the passive region. Reciprocating sliding tribocorrosion tests were carried out against technical grade ultra high molecular weight polyethylene, while fretting corrosion tests were carried out against alumina. The wear of the alloy is insignificant when sliding against polyethylene. However, depassivation does take place, but the tested alloy showed an ability to recover its passive state during sliding. The abrasivity of the alloy depends on the electrochemical conditions of the contact, while the wear of polyethylene proceeds through third body formation and material transfer. Under fretting corrosion conditions recovery of the passive state was also achieved. In a fretting contact wear of the alloy proceeds through plastic deformation of the bulk material and wear resistance depends on the electrochemical conditions. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

A methodology for the assessment of the tribocorrosion of passivating metallic materials

International audienceThe synergism between mechanical friction and corrosion may lead to an acceleration of the degradation of materials in sliding contacts exposed to the environment. Electrochemical measurements and sliding tests are proposed as a protocol suitable to decouple the material losses originating from the active material and the passive film, and to identify their electrochemical or mechanical nature. The corrosion resistance of a material, its ability to react onto chemical or mechanical attack, its susceptibility to tribocorrosion and the effect of a passive surface film on the coefficient of friction are evaluated. The proposed tribo-electrochemical protocol allows to evaluate the potential and risks of applying newly developed materials in sliding contacts, and to support the selection and implementation of materials in industry in applications where corrosion and wear are potential degradation processes. This protocol extends the existing Standard Guide ASTM G 119-04 'Determining Synergism between wear and Corrosion' for passivating metallic materials

Fretting-corrosion behavior of beta titanium alloys in simulated synovial fluid

Fretting-corrosion is a material degradation process resulting from the combined action of a corrosive environment and small displacement fretting wear. In this work, the fretting-corrosion behavior of Ti-12.5Mo, Ti-13Nb-13Zr, and Ti-29Nb-13Ta-4.6Zr, beta titanium alloys which are candidate biomaterials for joint prostheses was studied in Hank's balanced salt solution. Ti-6Al-4Fe alpha + beta titanium alloy was also tested for comparison. The open circuit potential, anodic current and friction coefficient were measured in situ, while the microstructure and volume of the wear track were characterized after testing. Ti-13Nb-13Zr and Ti-29Nb-13Ta-4.6Zr exhibited the ability to regain their passive state during fretting, while Ti-6Al-4Fe exhibited large dissolution pits around the wear track indicative of a widespread depassivation activated by fretting. The ability of these beta alloys to recover their passive state during fretting was related to the mechanical properties of the superficial passive layers and the evolution of the contact pressure defined by the wear of the alloy. The effects of the addition of synovial constituents, namely bovine serum albumin, hyaluronic acid and dipalmitoyphosphatidycholine on the fretting-corrosion of Ti-12.5Mo alloy were also studied. The addition of synovial constituents induced a decrease of the friction coefficient, the amount of elastic accommodation of the displacement and the wear rate of the alloy. (C) 2011 Elsevier B.V. All rights reserved.S