Application of the Zero-Order Reaction Rate Model and Transition State Theory to predict porous Ti6Al4V bending strength

Porous T16Al4V samples were produced by microsphere sintering. The Zero-Order Reaction Rate Model and Transition State Theory were used to model the sintering process and to estimate the bending strength of the porous samples developed. The evolution of the surface area during the sintering process was used to obtain sintering parameters (sintering constant, activation energy, frequency factor, constant of activation and Gibbs energy of activation). These were then correlated with the bending strength in order to obtain a simple model with which to estimate the evolution of the bending strength of the samples when the sintering temperature and time are modified: sigma(y) = P + B [In (T . t) - R.T./Delta G(g)]. Although the sintering parameters were obtained only for the microsphere sizes analysed here, the strength of intermediate sizes could easily be estimated following this model. (c) 2012 Elsevier B.V. All rights reserved.The authors are grateful to the Spanish Ministerio de Ciencia e Innovacion for supporting this study through project PET2008_0158_02. The translation of this paper was funded by the Universidad Politecnica de Valencia and the Universitat Jaume I.Reig Cerdá, L.; Amigó Borrás, V.; Busquets Mataix, DJ.; Calero, JA.; Ortiz Rosales, JL. (2012). Application of the Zero-Order Reaction Rate Model and Transition State Theory to predict porous Ti6Al4V bending strength. Materials Science and Engineering: C. 32(6):1621-1626. https://doi.org/10.1016/j.msec.2012.04.052S1621162632

Titanium cranioplasty in children and adolescents

Full thickness calvarial defects present considerable challenges to reconstructive surgeons. In paediatric cases, the use of biomaterials as a substrate for cranioplasty rather than autologous bone is controversial. Alloplastic cranioplasty in adults is supported by several large case series however long term outcome of biomaterial use in paediatric cases is limited. Retrospective seven year analysis of departmental database and clinical records identified 22 patients aged under 18 who had undergone 23 custom made titanium cranioplasties by a single surgeon using the same technique. Data including patient demographics, reason for craniectomy and complications experienced following surgery was obtained. The mean age at operation was 12 years 9 months. The mean defect size was 44.3cm2. No significant complications related to the cranioplasty were recorded in the early post operative period or during long term review (average follow up 4 years 6 months). No cranioplasty implant required removal. This retrospective case series shows that custom made patient specific titanium cranioplasty is a viable alternative to autologous bone as a reconstructive material in paediatric patients under specific circumstances

Effect of the Prostaglandin Derivative Prostaglandin E2-Glyceryl-Ester on the human P2Y6-Receptor and its Importance during Urinary Tract Infections

Prostanoid and purinergic signalling are essential for the proinflammatory component of acute and chronic kidney disease. Nucleotides are released early in response to cell perturbation, whereas the prostaglandin system is activated downstream. Interestingly, a direct effect of the COX-2 product prostaglandin E2-1-glyceryl ester (PGE2-G) on the UDP-sensitive P2Y6 receptor expressed in the proximal tubule is suggested. Thus, we hypothesized that PGE2-G amplifies renal inflammation directly via P2Y6-receptor activation. To verify the PGE2-G mediated P2Y6 activation, we used 132-1N1 astrocytoma cells devoid of P2 receptors for specific expression of the P2Y6 receptor. We monitored [Ca2+]i signalling by both life-cell microscopy and plate reader by detection of Fluo-4 fluorescence in human P2Y6 expressing 132-1N1 cells (hP2Y6 cells). Wild type 132-1N1 cells (WT cells) were used as negative control. The hP2Y6 cells were activated by UDP in a concentration-dependent manner. WT cells did not react to UDP but to carbachol. Surprisingly, stimulation of hP2Y6 cells with PGE2-G from several batches in concentrations from 10-11 to 10-6 M did not inflict any change in [Ca2+]i. We observed a PGE2-G-induced [Ca2+]i increase compared to vehicle control at concentrations of 10-4 M dissolved in DMSO. However, we detected a completely similar response in WT cells. PGE2-G in our preparations was confirmed by HPLC. Thus, our data cannot confirm a direct effect of PGE2-G on P2Y6 receptors and thus, does not support that this type of signalling is relevant during renal inflammation

Digital products and processes in dental technology

Following the VDMA guideline Industry 4.0 potential ways towards digitalization of production are illustrated using an example from dental technology. The special feature in medical engineering is the responsibility of the physician, particularly in the context of custom-made products. Data security, integrity, and traceability is mandatory in digital processes when responsibility is switching between parties, e.g. dental laboratory / practice. This article illustrates how those requirements can be met