The Many Lives of Stephen Pan

Stephen S.T. Pan \u2755 survived years of war and many brushes with death before starting a new life at IWU. At age 93, he looks back on his journey with both gratitude and amazement

Are ecstasy users biased toward endorsing somatic mental health symptoms? Results from a general community sample

Abstract Rationale Whether the reported poorer mental health of ecstasy users is due to a bias in endorsement of somatic symptoms has been postulated, but rarely examined. Objectives The purpose of this study is to investigate whether levels of ecstasy use were associated with differential probabilities of endorsing somatic mental health symptoms. Methods Current ecstasy users aged 24-30 years (n=316) were identified from a population-based Australian study. Measures included frequency of ecstasy, meth/amphetamine, and cannabis use and the Goldberg anxiety/ depression symptom scales

Intrinsic energy flow in laser-excited 3d ferromagnets

Ultrafast magnetization dynamics are governed by energy flow between electronic, magnetic, and lattice degrees of freedom. A quantitative understanding of these dynamics must be based on a model that agrees with experimental results for all three subsystems. However, ultrafast dynamics of the lattice remain largely unexplored experimentally. Here we combine femtosecond electron diffraction experiments of the lattice dynamics with energy-conserving atomistic spin dynamics (ASD) simulations and ab initio calculations to study the intrinsic energy flow in the 3d ferromagnets cobalt (Co) and iron (Fe). The simulations yield a good description of experimental data, in particular an excellent description of our experimental results for the lattice dynamics. We find that the lattice dynamics are influenced significantly by the magnetization dynamics due to the energy cost of demagnetization. Our results highlight the role of the spin system as the dominant heat sink in the first hundreds of femtoseconds. Together with previous findings for nickel [Zahn et al., Phys. Rev. Research 3, 023032 (2021)], our work demonstrates that energy-conserving ASD simulations provide a general and consistent description of the laser-induced dynamics in all three elemental 3d ferromagnets

Lattice dynamics and ultrafast energy flow between electrons, spins, and phonons in a 3d ferromagnet

The ultrafast dynamics of magnetic order in a ferromagnet are governed by the interplay between electronic, magnetic, and lattice degrees of freedom. In order to obtain a microscopic understanding of ultrafast demagnetization, information on the response of all three subsystems is required. A consistent description of demagnetization and microscopic energy flow, however, is still missing. Here, we combine a femtosecond electron diffraction study of the ultrafast lattice response of nickel to laser excitation with ab initio calculations of the electron-phonon interaction and energy-conserving atomistic spin dynamics simulations. Our model is in agreement with the observed lattice dynamics and previously reported electron and magnetization dynamics. Our approach reveals that the spin system is the dominating heat sink in the initial few hundred femtoseconds and implies a transient nonthermal state of the spins. Our results provide a clear picture of the microscopic energy flow between electronic, magnetic, and lattice degrees of freedom on ultrafast timescales and constitute a foundation for theoretical descriptions of demagnetization that are consistent with the dynamics of all three subsystems

Methane Flux from Drained Northern Peatlands: Effect of a Persistent Water Table Lowering on Flux

Measurements of CH4 flux from drained and undrained sites in three northern Ontario peatlands (a treed fen, a forested bog, and a treed bog) were made from the beginning of May to the end of October 1991. In the drained portions, the water table had been lowered between 0.1 and 0.5 m, compared to the water table of the undrained portion of the peatlands. The mean seasonal CH4 flux from the undrained portions of three peatlands was small, ranging from 0 to 8 mg m-2d-1, but similar to the CH4 flux from other treed and forested northern peatlands. The mean seasonal CH4 flux from the drained portion of the peatlands was either near zero or slightly negative (i.e., uptake): fluxes ranged from 0.1 to -0.4 mg m-2d-1. Profiles of CH4 in the air-filled pores in the unsaturated zone, and the water-filled pores of the saturated zone of the peat at the undrained sites, showed that all the CH4 produced at depth was consumed within 0.2 m of the water table and that atmospheric CH4 was consumed in the upper 0.15 m of the peatland. On the basis of laboratory incubations of peat slurries to determine CH4 production and consumption potentials, the lowering of the water table eliminated the near-surface zone of CH4 production that existed in the undrained peatland. However, drainage did not alter significantly the potential for CH4 oxidation between the water table and peatland surface but increased the thickness of the layer over which CH4 oxidation could take place. These changes occurred with a drop in the mean summer water table of only 0.1 m (from -0.2 to -0.3 m) suggesting that only a small negative change in soil moisture would be required to significantly reduce CH4 flux from northern peatlands

Dynamics of the photoinduced insulator-to-metal transition in a nickelate film

The control of materials properties with light is a promising approach towards the realization of faster and smaller electronic devices. With phases that can be controlled via strain, pressure, chemical composition or dimensionality, nickelates are good candidates for the development of a new generation of high performance and low consumption devices. Here we analyze the photoinduced dynamics in a single crystalline NdNiO$_3$ film upon excitation across the electronic gap. Using time-resolved reflectivity and resonant x-ray diffraction, we show that the pump pulse induces an insulator-to-metal transition, accompanied by the melting of the charge order. Finally we compare our results to similar studies in manganites and show that the same model can be used to describe the dynamics in nickelates, hinting towards a unified description of these photoinduced phase transitions.Comment: 17 pages, 6 figure

Protocol for the Smoking, Nicotine and Pregnancy (SNAP) trial: double-blind, placebo-randomised, controlled trial of nicotine replacement therapy in pregnancy

Background: Smoking in pregnancy remains a public health challenge. Nicotine replacement therapy (NRT) is effective for smoking cessation in non-pregnant people, but because women metabolise nicotine and cotinine much faster in pregnancy, it is unclear whether this will be effective for smoking cessation in pregnancy. The NHS Health Technology Assessment Programme (HTA)-funded smoking, nicotine and pregnancy ( SNAP) trial will investigate whether or not nicotine replacement therapy ( NRT) is effective, cost-effective and safe when used for smoking cessation by pregnant women. Methods/Design: Over two years, in 5 trial centres, 1050 pregnant women who are between 12 and 24 weeks pregnant will be randomised as they attend hospital for ante-natal ultrasound scans. Women will receive either nicotine or placebo transdermal patches with behavioural support. The primary outcome measure is biochemically-validated, self-reported, prolonged and total abstinence from smoking between a quit date ( defined before randomisation and set within two weeks of this) and delivery. At six months after childbirth self-reported maternal smoking status will be ascertained and two years after childbirth, self-reported maternal smoking status and the behaviour, cognitive development and respiratory symptoms of children born in the trial will be compared in both groups. Discussion: This trial is designed to ascertain whether or not standard doses of NRT ( as transdermal patches) are effective and safe when used for smoking cessation during pregnancy

Outcomes of a new slowly resorbable biosynthetic mesh (Phasix (TM)) in potentially contaminated incisional hernias : a prospective, multi-center, single-arm trial

Background: Resorbable biomaterials have been developed to reduce the amount of foreign material remaining in the body after hernia repair over the long-term. However, on the short-term, these resorbable materials should render acceptable results with regard to complications, infections, and reoperations to be considered for repair. Additionally, the rate of resorption should not be any faster than collagen deposition and maturation; leading to early hernia recurrence. Therefore, the objective of this study was to collect data on the short-term performance of a new resorbable biosynthetic mesh (Phasix (TM)) in patients requiring Ventral Hernia Working Group (VHWG) Grade 3 midline incisional hernia repair. Materials and methods: A prospective, multi-center, single-arm trial was conducted at surgical departments in 15 hospitals across Europe. Patients aged >= 18, scheduled to undergo elective Ventral Hernia Working Group Grade 3 hernia repair of a hernia larger than 10 cm(2) were included. Hernia repair was performed with Phasix (TM) Mesh in sublay position when achievable. The primary outcome was the rate of surgical site occurrence (SSO), including infections, that required intervention until 3 months after repair. Results: In total, 84 patients were treated with Phasix (TM) Mesh. Twenty-two patients (26.2%) developed 32 surgical site occurrences. These included 11 surgical site infections, 9 wound dehiscences, 7 seromas, 2 hematomas, 2 skin necroses, and 1 fistula. No significant differences in surgical site occurrence development were found between groups repaired with or without component separation technique, and between clean-contaminated or contaminated wound sites. At three months, there were no hernia recurrences. Conclusion: Phasix (TM) Mesh demonstrated acceptable postoperative surgical site occurrence rates in patients with a Ventral Hernia Working Group Grade 3 hernia. Longer follow-up is needed to evaluate the recurrence rate and the effects on quality of life. This study is ongoing through 24 months of follow-up