title: Low-cost Ti alloys: Assessment of their microstructure, mechanical properties, corrosion behaviour, and biological response

authors: Bolzoni, Leandro

subjects: implants

abstract: Orthopaedic and dental implants, the majority of which are made from titanium alloys, face the crucial challenge of both inducing osteogenesis whilst inhibiting bacterial biofilm formation in an economical manner over the life of the implant. This study introduces an innovative strategy combining cost-effective alloying elements, selected due to their reported biological benefits, for developing new titanium alloys that achieve a tailorable mechanical, corrosion, and biological response. The combination of alloying and manufacturing results in homogeneous materials characterised by a lamellar microstructure. The developed low-cost Ti alloys have a maximum ultimate compression strength of 659 MPa, maximum tensile yield stress of 606 MPa, and maximum elongation of 8.3% without failing catastrophically. The alloys do not degrade as abiotic corrosion is significantly hampered by their intrinsic passivation behaviour (maximum corrosion rate of 8.9 μm/year), and have adjustable surface wettability with contact angles in the 60-81° range. Consequently, stomal cell attachment, cytotoxicity and cytokine production (IL-6 and TGF-β1), and antibacterial rate on S. aureus are consistent and comparable to those of current implnat materials. Based on these characteristics, the low-cost Ti alloys are promising materials for load-bearing biomedical devices.

text: Low-cost Ti alloys: Assessment of their microstructure, mechanical properties, corrosion behaviour, and biological response Orthopaedic and dental implants, the majority of which are made from titanium alloys, face the crucial challenge of both inducing osteogenesis whilst inhibiting bacterial biofilm formation in an economical manner over the life of the implant. This study introduces an innovative strategy combining cost-effective alloying elements, selected due to their reported biological benefits, for developing new titanium alloys that achieve a tailorable mechanical, corrosion, and biological response. The combination of alloying and manufacturing results in homogeneous materials characterised by a lamellar microstructure. The developed low-cost Ti alloys have a maximum ultimate compression strength of 659 MPa, maximum tensile yield stress of 606 MPa, and maximum elongation of 8.3% without failing catastrophically. The alloys do not degrade as abiotic corrosion is significantly hampered by their intrinsic passivation behaviour (maximum corrosion rate of 8.9 μm/year), and have adjustable surface wettability with contact angles in the 60-81° range. Consequently, stomal cell attachment, cytotoxicity and cytokine production (IL-6 and TGF-β1), and antibacterial rate on S. aureus are consistent and comparable to those of current implnat materials. Based on these characteristics, the low-cost Ti alloys are promising materials for load-bearing biomedical devices.

year: 2026

title: Predictions and simulations of cortical dynamics during natural sleep using a continuum approach

authors: Wilson, Marcus T.

subjects: REM

abstract: In this paper we use a continuum model in two spatial dimensions to study the dynamics of the cortex during natural sleep, including explicitly the effects of two key neuromodulators. The model predicts that a number of states could be available to the cortex. We identify two of these with slow-wave sleep and rapid eye movement (REM) sleep, and focus on the transition between the two. Eigenvalue analysis of the linearized model, together with simulations on a two-dimensional grid, show that a number of oscillatory states exist; the occurrence of these is particularly dependent upon the duration in time of the inhibitory postsynaptic potential. These oscillatory states are similar to the cortical slow oscillation and certain types of seizure. Power spectra are evaluated for different parameter sets and compare favorably with experiment. Grid simulations show that transitions between cortical states (e.g., slow-wave to REM) can be seeded at any point in space by random fluctuations in subcortical input.

text: Predictions and simulations of cortical dynamics during natural sleep using a continuum approach In this paper we use a continuum model in two spatial dimensions to study the dynamics of the cortex during natural sleep, including explicitly the effects of two key neuromodulators. The model predicts that a number of states could be available to the cortex. We identify two of these with slow-wave sleep and rapid eye movement (REM) sleep, and focus on the transition between the two. Eigenvalue analysis of the linearized model, together with simulations on a two-dimensional grid, show that a number of oscillatory states exist; the occurrence of these is particularly dependent upon the duration in time of the inhibitory postsynaptic potential. These oscillatory states are similar to the cortical slow oscillation and certain types of seizure. Power spectra are evaluated for different parameter sets and compare favorably with experiment. Grid simulations show that transitions between cortical states (e.g., slow-wave to REM) can be seeded at any point in space by random fluctuations in subcortical input.

year: 2005

title: “It is about enabling Tino Rangatiratanga and Mana Motuhake”: An analysis of submissions on the Pae Ora (Healthy Futures) Bill 2021 endorsing a Māori health authority

authors: Edmonds, Moengaroa

subjects: Health Equity

abstract: Indigenous leadership in healthcare is one way for Indigenous peoples to exercise sovereignty over their health. In Aotearoa New Zealand, the establishment of the Māori Health Authority (MHA) was grounded in a decades-long imperative to address Māori health inequities and operationalise te Tiriti o Waitangi within the health system. However, the populist National-led coalition government formed in November 2023 included the abolishment of the MHA in their first 100-day plan and eventually disestablished it in February 2024. This study analysed 155 public group submissions on the Pae Ora (Healthy Futures) Bill made in 2021 and representing health professionals, iwi, hapū, and community groups. Core themes endorsing the MHA as a statutory entity included honouring te Tiriti, advocating for Māori-led solutions to health inequities, decolonising health systems, and affirming Indigenous rights. The political decision to remove the MHA is antithetical to the explicit endorsement statements made by an overwhelming majority of group submitters with expertise in health organisational structures and healthcare provision. Our study has implications for future local and international research in documenting counter-narratives for Indigenous struggles in health systems.

text: “It is about enabling Tino Rangatiratanga and Mana Motuhake”: An analysis of submissions on the Pae Ora (Healthy Futures) Bill 2021 endorsing a Māori health authority Indigenous leadership in healthcare is one way for Indigenous peoples to exercise sovereignty over their health. In Aotearoa New Zealand, the establishment of the Māori Health Authority (MHA) was grounded in a decades-long imperative to address Māori health inequities and operationalise te Tiriti o Waitangi within the health system. However, the populist National-led coalition government formed in November 2023 included the abolishment of the MHA in their first 100-day plan and eventually disestablished it in February 2024. This study analysed 155 public group submissions on the Pae Ora (Healthy Futures) Bill made in 2021 and representing health professionals, iwi, hapū, and community groups. Core themes endorsing the MHA as a statutory entity included honouring te Tiriti, advocating for Māori-led solutions to health inequities, decolonising health systems, and affirming Indigenous rights. The political decision to remove the MHA is antithetical to the explicit endorsement statements made by an overwhelming majority of group submitters with expertise in health organisational structures and healthcare provision. Our study has implications for future local and international research in documenting counter-narratives for Indigenous struggles in health systems.

year: 2025