Solubility of zinc oxide-eugenol and calcium hydroxide cements in simulated dentinal fluid

The solubility of four dental cement bases was measured in simulated dentinal fluid and distilled water to evaluate the relevancy of the American Dental Association solubility test for cement bases in contact with vital dentine. A simulated dentinal fluid was formulated utilizing glucose, distilled water, and sterile human plasma. Cement-base samples were immersed in either distilled water or simulated dentinal fluid at 37°C in a shaker water-bath for 1, 2, or 3 months. Weight loss values were compared utilizing a three-way analysis of variance. Zinc oxide-eugenol cements were significantly more soluble in simulated dentinal fluid than distilled water, while the calcium hydroxide cement bases were significantly more soluble in distilled water than simulated dentinal fluid.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73127/1/j.1365-2842.1989.tb01365.x.pd

Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics

An n(++)-GaAs/p(++)-AlGaAs tunnel junction with a peak current density of 10 100Acm(-2) is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10 000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500Acm(-2) and a voltage drop at 10 000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations

Multinational and large national corporations and climateadaptation: are we asking the right questions? A review ofcurrent knowledge and a new research perspective

Adapting to climate change requires the engagement of all actors in society. Until recently, the predominant research focus has been on governments, communities and the third sector as key actors in the adaptation process. Yet, there is a growing emphasis internationally on understanding the role of and the need to engage businesses in adaptation given their potential to finance projects, develop technologies and innovative solutions, and enhance the scale and cost-effectiveness of certain adaptation measures. Large national and multinational corporations are among the key actors in this respect. Already, many of these corporations are purportedly taking steps to adapt their operations to climate change. Some stated reasons for their engagement include minimising potential impacts on value chains, improving resource efficiency, enhancing production of sustainable raw materials, and supporting customers’, suppliers’ and communities’ climate change adaptation efforts. However, there is a paucity of work analysing adaptation actions by these corporations, their motivations and contribution to broader adaptation and climate resilient development efforts, as well as possible instances of maladaptation. We apply a three-tier framework on drivers, responses and outcomes to examine the state of knowledge according to recent literature on private sector and corporate adaptation to climate change. Our review highlights that the literature on the impact and outcomes of corporate adaptation actions is sparse and we consider the implications for future research. Our analysis concludes with a reflection on the relevance of corporate-led adaptation – for the companies themselves, policy-makers at all scales, as well as society at large

Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model

Several firing patterns experimentally observed in neural populations have been successfully correlated to animal behavior. Population bursting, hereby regarded as a period of high firing rate followed by a period of quiescence, is typically observed in groups of neurons during behavior. Biophysical membrane-potential models of single cell bursting involve at least three equations. Extending such models to study the collective behavior of neural populations involves thousands of equations and can be very expensive computationally. For this reason, low dimensional population models that capture biophysical aspects of networks are needed. \noindent The present paper uses a firing-rate model to study mechanisms that trigger and stop transitions between tonic and phasic population firing. These mechanisms are captured through a two-dimensional system, which can potentially be extended to include interactions between different areas of the nervous system with a small number of equations. The typical behavior of midbrain dopaminergic neurons in the rodent is used as an example to illustrate and interpret our results. \noindent The model presented here can be used as a building block to study interactions between networks of neurons. This theoretical approach may help contextualize and understand the factors involved in regulating burst firing in populations and how it may modulate distinct aspects of behavior.Comment: 25 pages (including references and appendices); 12 figures uploaded as separate file

Independent optical excitation of distinct neural populations

Optogenetic tools enable examination of how specific cell types contribute to brain circuit functions. A long-standing question is whether it is possible to independently activate two distinct neural populations in mammalian brain tissue. Such a capability would enable the study of how different synapses or pathways interact to encode information in the brain. Here we describe two channelrhodopsins, Chronos and Chrimson, discovered through sequencing and physiological characterization of opsins from over 100 species of alga. Chrimson's excitation spectrum is red shifted by 45 nm relative to previous channelrhodopsins and can enable experiments in which red light is preferred. We show minimal visual system–mediated behavioral interference when using Chrimson in neurobehavioral studies in Drosophila melanogaster. Chronos has faster kinetics than previous channelrhodopsins yet is effectively more light sensitive. Together these two reagents enable two-color activation of neural spiking and downstream synaptic transmission in independent neural populations without detectable cross-talk in mouse brain slice.PostprintPeer reviewe

Evaluation of NHMRC funded research completed in 1992, 1997 and 2003: gains in knowledge, health and wealth

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Objective: To report on strategies for, and outcomes of, evaluation of knowledge (publications), health and wealth (commercial) gains from medical research funded by the Australian Government through the National Health and Medical Research Council (NHMRC). Design and methods: End-of-grant reports submitted by researchers within 6 months of completion of NHMRC funded project grants which terminated in 2003 were used to capture self-reported publication number, health and wealth gains. Self-reported gains were also examined in retrospective surveys of grants completed in 1992 and 1997 and awards primarily supporting people (“people awards”) held between 1992 and 2002. Results: The response rate for the 1992 sample was too low for meaningful analysis. The mean number of publications per grant in the basic biomedical, clinical and health services research areas was very similar in 1997 and 2003. The publication output for population health was somewhat higher in the 2003 than in the 1997 analysis. For grants completed in 1997, 24% (31/131) affected clinical practice; 14% (18/131) public health practice; 9% (12/131) health policy; and 41% (54/131) had commercial potential with 20% (26/131) resulting in patents. Most respondents (89%) agreed that NHMRC people awards improved their career prospects. Interpretation is limited by the relatively low response rates (50% or less). Conclusions: A mechanism has been developed for ongoing assessment of NHMRC funded research. This process will improve accountability to the community and to government, and refine current funding mechanisms to most efficiently deliver health and economic returns for Australia.Bronwyn A Kingwell, Gary P Anderson, Stephen J Duckett, Elizabeth A Hoole, Lisa R Jackson-Pulver, Levon M Khachigian, Meg E Morris, David M Roder, Jan Rothwell-Short and Andrew J Wilson for the National Health and Medical Research Council Evaluations and Outcomes Working Committe

CD26-negative and CD26-positive tissue-resident fibroblasts contribute to functionally distinct CAF subpopulations in breast cancer

The origin of cancer-associated fibroblasts (CAFs) in cancer remains to be identified. Here, single-cell transcriptomics, in vivo and in vitro studies suggest that CD26+ and CD26- normal fibroblasts transform into distinct CAF subpopulations in mouse models of breast cancer

Eclampsia in Australia and New Zealand: A prospective population-based study

Background: Eclampsia is a serious consequence of pre-eclampsia. There are lim-ited data from Australia and New Zealand (ANZ) on eclampsia.Aim: To determine the incidence, management and perinatal outcomes of women with eclampsia in ANZ.Materials and Methods: A two-year population-based descriptive study, using the Australasian Maternity Outcomes Surveillance System (AMOSS), carried out in 263 sites in Australia, and all 24 New Zealand maternity units, during a staggered implementation over 2010-2011. Eclampsia was defined as one or more seizures during pregnancy or postpartum (up to 14 days) in any woman with clinical evi-dence of pre-eclampsia.Results: Of 136 women with eclampsia, 111 (83%) were in Australia and 25 (17%) in New Zealand. The estimated incidence of eclampsia was 2.2 (95% confidence inter-val (CI) 1.9-2.7) per 10 000 women giving birth. Aboriginal and Torres Strait Islander women were over-represented in Australia (n = 9; 8.1%). Women with antepartum eclampsia (n = 58, 42.6%) were more likely to have a preterm birth (P = 0.04). Sixty-three (47.4%) women had pre-eclampsia diagnosed prior to their first eclamptic seizure of whom 19 (30.2%) received magnesium sulphate prior to the first seizure. Nearly all women (n = 128; 95.5%) received magnesium sulphate post-seizure. No woman received prophylactic aspirin during pregnancy. Five women had a cer-ebrovascular haemorrhage, and there were five known perinatal deaths.Conclusions: Eclampsia is an uncommon consequence of pre-eclampsia in ANZ. There is scope to reduce the incidence of this condition, associated with often cata-strophic morbidity, through the use of low-dose aspirin and magnesium sulphate in women at higher risk.Funding for AMOSS was through the National Health and Medical Research Council (App ID 510298). In NZ, AMOSS is supported and funded by the Perinatal and Maternal Mortality Review Committee