title: Neutron frequency windows and the protein dynamical transition

authors: Becker, Torsten

abstract: Proteins undergo an apparent dynamical transition on temperature variation that has been correlated with the onset of function. The transition in the mean-square displacement, ∆r2 , that is observed using a spectrometer or computer simulation, depends on the relationship between the timescales of the relaxation processes activated and the timescale accessible to the instrument or simulation. Models are described of two extreme situations—an "equilibrium" model, in which the long-time dynamics changes with temperature and all motions are resolved by the instrument used; and a "frequency window" model, in which there is no change in the long-time dynamics but as the temperature increases, the relaxation frequencies move into the instrumental range. Here we demonstrate that the latter, frequency-window model can describe the temperature and timescale dependences of both the intermediate neutron scattering function and  ∆r2  derived from molecular dynamics simulations of a small protein in a cryosolution. The frequency-window model also describes the energy-resolution and temperature-dependences of  ∆r2  obtained from experimental neutron scattering on glutamate dehydrogenase in the same solvent. Although equilibrium effects should also contribute to dynamical transitions in proteins, the present results suggests that frequency-window effects can play a role in the simulations and experiments examined. Finally, misquotations of previous findings are discussed in the context of solvent activation of protein dynamics and the possible relationship of this to activity.

text: Neutron frequency windows and the protein dynamical transition Proteins undergo an apparent dynamical transition on temperature variation that has been correlated with the onset of function. The transition in the mean-square displacement, ∆r2 , that is observed using a spectrometer or computer simulation, depends on the relationship between the timescales of the relaxation processes activated and the timescale accessible to the instrument or simulation. Models are described of two extreme situations—an "equilibrium" model, in which the long-time dynamics changes with temperature and all motions are resolved by the instrument used; and a "frequency window" model, in which there is no change in the long-time dynamics but as the temperature increases, the relaxation frequencies move into the instrumental range. Here we demonstrate that the latter, frequency-window model can describe the temperature and timescale dependences of both the intermediate neutron scattering function and  ∆r2  derived from molecular dynamics simulations of a small protein in a cryosolution. The frequency-window model also describes the energy-resolution and temperature-dependences of  ∆r2  obtained from experimental neutron scattering on glutamate dehydrogenase in the same solvent. Although equilibrium effects should also contribute to dynamical transitions in proteins, the present results suggests that frequency-window effects can play a role in the simulations and experiments examined. Finally, misquotations of previous findings are discussed in the context of solvent activation of protein dynamics and the possible relationship of this to activity.

year: 2004-09

title: Contraceptive use in lesbian and bisexual women: Findings from the Australian Longitudinal Study on Women’s Health

authors: Ellis, Sonja J.

abstract: Contraceptive use is a key part of sexual and reproductive health for women, yet few studies have explored contraceptive use patterns in lesbian and bisexual women born between 1989 and 1995. Analysing data from an existing cohort study of reproductive-aged women this study explores contraceptive use among lesbian and bisexual women in Australia. Findings of the study showed that lesbians were least likely to use contraceptives compared to heterosexual women and that bisexual women used short-acting hormonal methods at lower rates and long-acting reversible contraception (LARCs) such as IUDs and implants at higher rates than their heterosexual peers. There was also a range of changes in contraceptive use across time including a decrease in use of both short-acting hormonal contraception and LARCs in combination with condoms while the use of LARCs on their own increased. The findings of this study also indicate that young lesbian and bisexual women are not only likely to use more than one type of contraception, but that their choice of contraception is dynamic and likely to change over time. This paper highlights the need for research that specifically explores the underlying reasons for patterns of, and changes in, contraceptive use among lesbian and bisexual women to better understand the contraceptive counselling needs of this group.

text: Contraceptive use in lesbian and bisexual women: Findings from the Australian Longitudinal Study on Women’s Health Contraceptive use is a key part of sexual and reproductive health for women, yet few studies have explored contraceptive use patterns in lesbian and bisexual women born between 1989 and 1995. Analysing data from an existing cohort study of reproductive-aged women this study explores contraceptive use among lesbian and bisexual women in Australia. Findings of the study showed that lesbians were least likely to use contraceptives compared to heterosexual women and that bisexual women used short-acting hormonal methods at lower rates and long-acting reversible contraception (LARCs) such as IUDs and implants at higher rates than their heterosexual peers. There was also a range of changes in contraceptive use across time including a decrease in use of both short-acting hormonal contraception and LARCs in combination with condoms while the use of LARCs on their own increased. The findings of this study also indicate that young lesbian and bisexual women are not only likely to use more than one type of contraception, but that their choice of contraception is dynamic and likely to change over time. This paper highlights the need for research that specifically explores the underlying reasons for patterns of, and changes in, contraceptive use among lesbian and bisexual women to better understand the contraceptive counselling needs of this group.

year: 2026

title: Haumanu hauora: A commentary on strengthening health institution responsiveness to Māori health in the face of climate change

authors: Masters-Awatere, Bridgette

abstract: Climate change is the biggest threat to humanity through compounding ecological disasters. A focus on global averages tends to hide dramatic differences and mask health disparities that exist for Indigenous people. For 21 years, district health boards (DHBs) were responsible for providing or funding the provision of health services across Aotearoa. The introduction of the Pae Ora (Healthy Futures) Act 2022 disestablished DHBs and offered an opportunity to reshape health in ways that give serious consideration to climate change impacts. The need to give greater consideration to Indigenous people in climate change conversations is essential. The Waitangi Tribunal highlights areas where the Crown needs to work to improve Māori health outcomes. A clear deficit in existing policy process means a lack of preparedness for the intersecting health crises vulnerable Māori will experience in the face of climate change. Structural change is needed to strengthen health institution responsiveness to Māori health needs.

text: Haumanu hauora: A commentary on strengthening health institution responsiveness to Māori health in the face of climate change Climate change is the biggest threat to humanity through compounding ecological disasters. A focus on global averages tends to hide dramatic differences and mask health disparities that exist for Indigenous people. For 21 years, district health boards (DHBs) were responsible for providing or funding the provision of health services across Aotearoa. The introduction of the Pae Ora (Healthy Futures) Act 2022 disestablished DHBs and offered an opportunity to reshape health in ways that give serious consideration to climate change impacts. The need to give greater consideration to Indigenous people in climate change conversations is essential. The Waitangi Tribunal highlights areas where the Crown needs to work to improve Māori health outcomes. A clear deficit in existing policy process means a lack of preparedness for the intersecting health crises vulnerable Māori will experience in the face of climate change. Structural change is needed to strengthen health institution responsiveness to Māori health needs.

year: 2025