Nuclear Force Imprints Revealed on the Elastic Scattering of Protons with

How does nature hold together protons and neutrons to form the wide variety of complex nuclei in the Universe? Describing many-nucleon systems from the fundamental theory of quantum chromodynamics has been the greatest challenge in answering this question. The chiral effective field theory description of the nuclear force now makes this possible but requires certain parameters that are not uniquely determined. Defining the nuclear force needs identification of observables sensitive to the different parametrizations. From a measurement of proton elastic scattering on ^{10}C at TRIUMF and ab initio nuclear reaction calculations, we show that the shape and magnitude of the measured differential cross section is strongly sensitive to the nuclear force prescription.

Scattering of the Halo Nucleus

Angular distributions of the elastic, inelastic, and breakup cross sections of the halo nucleus ^{11}Be on ^{197}Au were measured at energies below (E_{lab}=31.9 MeV) and around (39.6 MeV) the Coulomb barrier. These three channels were unambiguously separated for the first time for reactions of ^{11}Be on a high-Z target at low energies. The experiment was performed at TRIUMF (Vancouver, Canada). The differential cross sections were compared with three different calculations: semiclassical, inert-core continuum-coupled-channels and continuum-coupled-channels ones with including core deformation. These results show conclusively that the elastic and inelastic differential cross sections can only be accounted for if core-excited admixtures are taken into account. The cross sections for these channels strongly depend on the B(E1) distribution in ^{11}Be, and the reaction mechanism is sensitive to the entanglement of core and halo degrees of freedom in ^{11}Be.

Longitudinal employment outcomes of an early intervention vocational rehabilitation service for people admitted to rehabilitation with a traumatic spinal cord injury.

STUDY DESIGN: Longitudinal cohort design. OBJECTIVES: First, to explore the longitudinal outcomes for people who received early intervention vocational rehabilitation (EIVR); second, to examine the nature and extent of relationships between contextual factors and employment outcomes over time. SETTING: Both inpatient and community-based clients of a Spinal Community Integration Service (SCIS). METHODS: People of workforce age undergoing inpatient rehabilitation for traumatic spinal cord injury were invited to participate in EIVR as part of SCIS. Data were collected at the following three time points: discharge and at 1 year and 2+ years post discharge. Measures included the spinal cord independence measure, hospital anxiety and depression scale, impact on participation and autonomy scale, numerical pain-rating scale and personal wellbeing index. A range of chi square, correlation and regression tests were undertaken to look for relationships between employment outcomes and demographic, emotional and physical characteristics. RESULTS: Ninety-seven participants were recruited and 60 were available at the final time point where 33% (95% confidence interval (CI): 24-42%) had achieved an employment outcome. Greater social participation was strongly correlated with wellbeing (ρ=0.692), and reduced anxiety (ρ=-0.522), depression (ρ=-0.643) and pain (ρ=-0.427) at the final time point. In a generalised linear mixed effect model, education status, relationship status and subjective wellbeing increased significantly the odds of being employed at the final time point. Tertiary education prior to injury was associated with eight times increased odds of being in employment at the final time point; being in a relationship at the time of injury was associated with increased odds of being in employment of more than 3.5; subjective wellbeing, while being the least powerful predictor was still associated with increased odds (1.8 times) of being employed at the final time point. CONCLUSIONS: EIVR shows promise in delivering similar return-to-work rates as those traditionally reported, but sooner. The dynamics around relationships, subjective wellbeing, social participation and employment outcomes require further exploration.

High-Precision Half-Life Measurements for the Superallowed ß

Precision measurements of superallowed Fermi ß-decay transitions, particularly for the lightest superallowed emitters ^{10}C and ^{14}O, set stringent limits on possible scalar current contributions to the weak interaction. In the present work, a discrepancy between recent measurements of the ^{10}C half-life is addressed through two high-precision half-life measurements, via γ-ray photopeak and ß counting, that yield consistent results for the ^{10}C half-life of T_{1/2}=19.2969±0.0074 s and T_{1/2}=19.3009±0.0017 s, respectively. The latter is the most precise superallowed ß-decay half-life measurement reported to date and the first to achieve a relative precision below 10^{-4}. A fit to the world superallowed ß-decay data including the ^{10}C half-life measurements reported here yields b_{F}=-0.0018±0.0021 (68% C.L.) for the Fierz interference term and C_{S}/C_{V}=+0.0009±0.0011 for the ratio of the weak scalar to vector couplings assuming left-handed neutrinos.

Evidence of soft dipole resonance in

The first conclusive evidence of a dipole resonance in ^{11}Li having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03±0.03 MeV with a width of 0.51±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in ^{11}Li. The first ab initio calculations in the coupled cluster framework are also presented.

Selective PEGylation of Parylene-C/SiO2 Substrates for Improved Astrocyte Cell Patterning.

Controlling the spatial distribution of glia and neurons in in vitro culture offers the opportunity to study how cellular interactions contribute to large scale network behaviour. A recently developed approach to cell-patterning uses differential adsorption of animal-serum protein on parylene-C and SiO2 surfaces to enable patterning of neurons and glia. Serum, however, is typically poorly defined and generates reproducibility challenges. Alternative activation methods are highly desirable to enable patterning without relying on animal serum. We take advantage of the innate contrasting surface chemistries of parylene-C and SiO2 to enable selective bonding of polyethylene glycol SiO2 surfaces, i.e. PEGylation, rendering them almost completely repulsive to cell adhesion. As the reagents used in the PEGylation protocol are chemically defined, the reproducibility and batch-to-batch variability complications associated with the used of animal serum are avoided. We report that PEGylated parylene-C/SiO2 substrates achieve a contrast in astrocyte density of 65:1 whereas the standard serum-immersion protocol results in a contrast of 5.6:1. Furthermore, single-cell isolation was significantly improved on PEGylated substrates when astrocytes were grown on close-proximity parylene-C nodes, whereas isolation was limited on serum-activated substrates due tolerance for cell adhesion on serum-adsorbed SiO2 surfaces.

Patterning of functional human astrocytes onto parylene-C/SiO2 substrates for the study of Ca2+ dynamics in astrocytic networks.

OBJECTIVE: Recent literature suggests that astrocytes form organized functional networks and communicate through transient changes in cytosolic Ca2+. Traditional techniques to investigate network activity, such as pharmacological blocking or genetic knockout, are difficult to restrict to individual cells. The objective of this work is to develop cell-patterning techniques to physically manipulate astrocytic interactions to enable the study of Ca2+ in astrocytic networks. APPROACH: We investigate how an in vitro cell-patterning platform that utilizes geometric patterns of parylene-C on SiO2 can be used to physically isolate single astrocytes and small astrocytic networks. MAIN RESULTS: We report that single astrocytes are effectively isolated on 75 × 75 µm square parylene nodes, whereas multi-cellular astrocytic networks are isolated on larger nodes, with the mean number of astrocytes per cluster increasing as a function of node size. Additionally, we report that astrocytes in small multi-cellular clusters exhibit spatio-temporal clustering of Ca2+ transients. Finally, we report that the frequency and regularity of Ca2+ transients was positively correlated with astrocyte connectivity. SIGNIFICANCE: The significance of this work is to demonstrate how patterning hNT astrocytes replicates spatio-temporal clustering of Ca2+ signalling that is observed in vivo but not in dissociated in vitro cultures. We therefore highlight the importance of the structure of astrocytic networks in determining ensemble Ca2+ behaviour.

Nanosecond UV lasers stimulate transient Ca2+ elevations in human hNT astrocytes.

OBJECTIVE: Astrocytes respond to various stimuli resulting in intracellular Ca2+ signals that can propagate through organized functional networks. Recent literature calls for the development of techniques that can stimulate astrocytes in a fast and highly localized manner to emulate more closely the characteristics of astrocytic Ca2+ signals in vivo. APPROACH: In this article we demonstrate, for the first time, how nanosecond UV lasers are capable of reproducibly stimulating Ca2+ transients in human hNT astrocytes. MAIN RESULTS: We report that laser pulses with a beam energy of 4-29 µJ generate transient increases in cytosolic Ca2+. These Ca2+ transients then propagate to adjacent astrocytes as intercellular Ca2+ waves. SIGNIFICANCE: We propose that nanosecond laser stimulation provides a valuable tool for enabling the study of Ca2+ dynamics in human astrocytes at both a single cell and network level. Compared to previously developed techniques nanosecond laser stimulation has the advantage of not requiring loading of photo-caged or -sensitising agents, is non-contact, enables stimulation with a high spatiotemporal resolution and is comparatively cost effective.

Hazard perception skills of young drivers with Attention Deficit Hyperactivity Disorder (ADHD) can be improved with computer based driver training: An exploratory randomised controlled trial.

BACKGROUND: Young drivers with Attention Deficit Hyperactivity Disorder (ADHD) are at higher risk of road traffic injuries than their peers. Increased risk correlates with poor hazard perception skill. Few studies have investigated hazard perception training using computer technology with this group of drivers. OBJECTIVES: *Determine the presence and magnitude of the between-group and within- subject change in hazard perception skills in young drivers with ADHD who receive Drive Smart training. *Determine whether training-facilitated change in hazard perception is maintained over time. METHODS: This was a feasibility study, randomised control trial conducted in Australia. The design included a delayed treatment for the control group. Twenty-five drivers with a diagnosis of ADHD were randomised to the Immediate Intervention or Delayed Intervention group.The Immediate Intervention group received a training session using a computer application entitled Drive Smart. The Delayed Intervention group watched a documentary video initially (control condition), followed by the Drive Smart computer training session. The participant's hazard perception skill was measured using the Hazard Perception Test (HPT). FINDINGS: After adjusting for baseline scores, there was a significant betweengroup difference in post-intervention HPT change scores in favour of the Immediate Intervention group. The magnitude of the effect was large. There was no significant within-group delayed intervention effect. A significant maintenance effect was found at 6-week follow-up for the Immediate Intervention group. CONCLUSIONS: The hazard perception skills of participants improved following training with large effect size and some maintenance of gain. A multimodal approach to training is indicated to facilitate maintenance. A full-scale trial is feasible.

Human astrocytic grid networks patterned in parylene-C inlayed SiO2 trenches.

Recent literature suggests that glia, and in particular astrocytes, should be studied as organised networks which communicate through gap junctions. Astrocytes, however, adhere to most surfaces and are highly mobile cells. In order to study, such organised networks effectively in vitro it is necessary to influence them to pattern to certain substrates whilst being repelled from others and to immobilise the astrocytes sufficiently such that they do not continue to migrate further whilst under study. In this article, we demonstrate for the first time how it is possible to facilitate the study of organised patterned human astrocytic networks using hNT astrocytes in a SiO2 trench grid network that is inlayed with the biocompatible material, parylene-C. We demonstrate how the immobilisation of astrocytes lies in the depth of the SiO2 trench, determining an optimum trench depth and that the optimum patterning of astrocytes is a consequence of the parylene-C inlay and the grid node spacing. We demonstrate high fidelity of the astrocytic networks and demonstrate that functionality of the hNT astrocytes through ATP evoked calcium signalling is also dependent on the grid node spacing. Finally, we demonstrate that the location of the nuclei on the grid nodes is also a function of the grid node spacing. The significance of this work, is to describe a suitable platform to facilitate the study of hNT astrocytes from the single cell level to the network level to improve knowledge and understanding of how communication links to spatial organisation at these higher order scales and trigger in vitro research further in this area with clinical applications in the area of epilepsy, stroke and focal cerebral ischemia.

18F-labeled benzamides for studying the dopamine D2 receptor with positron emission tomography.

Two series of (N-benzylpiperidin-4-yl)- and (9-azabicyclo[3.3.1]nonan- 3 beta-yl)benzamides were prepared, and in vitro binding assays were used to measure the affinity of these compounds for dopamine D2, dopamine D3, serotonin 5-HT2, and alpha 2-adrenergic receptors. The results of these studies indicated compounds 23, 26b, and 34 have the selectivity needed for in vivo studies of the D2 (and possibly D3) receptors. 18F-Labeled analogues of 23, 26b and 34 were prepared by N-alkylation of the corresponding desbenzyl precursors with [18F]-4-fluorobenzyl iodide. Preliminary in vivo studies demonstrated that [18F]-23 and [18F]-26b are suitable candidates for further evaluation in positron emission tomography imaging studies. The slow rate of washout of [18F]-34 from nondopaminergic regions and its comparatively high lipophilicity indicates that this compound may not be suitable for imaging studies because of a high level of nonspecific binding.

The use of [18F]4-fluorobenzyl iodide (FBI) in PET radiotracer synthesis: model alkylation studies and its application in the design of dopamine D1 and D2 receptor-based imaging agents.

[18F]4-Fluorobenzyl iodide ([18F]FBI) was prepared, and a series of model alkylation studies were conducted to determine its chemical reactivity toward nitrogen and sulfur nucleophiles of varying nucleophilicities. [18F]FBI was found to react rapidly with secondary amines and anilines to give the corresponding N-[18F]4-fluorobenzyl analogue in high yield. Amides and thiol groups required the use of a base catalyst. The utility of [18F]FBI was documented by investigation of dopamine D1 and D2 receptor-based radiotracers.

Breast self-examination in an urban population: estimates of prevalence and quality of performance.

Interview data from 434 women (aged greater than or equal to 20 years) in two Wellington suburban areas were used to estimate the prevalence and quality of performance of breast self-examination. Although 98% of women were familiar with breast self-examination, and 73% had performed it at least once, only 39% did so at least monthly. Its practice was significantly more common in the middle years (30-59), among Europeans, and in women with tertiary education. Thoroughness or quality of performance was assessed by comparison with Cancer Society recommendations. Scores for examination technique were generally high (mean = 73%) compared with those assessing timing (mean = 47.5%) and conditions under which breast self-examination was performed (mean = 43.3%). Results from this study were compared with 1975-76 New Zealand survey data which produced lower estimates of the prevalence of monthly breast self-examination. Both studies found that more than a quarter of women have never practiced it. Future research and intervention efforts should be directed toward this group of women.

Selection for rehabilitation: acute care discharge patterns for stroke and orthopaedic patients.

This study aimed to develop predictive models to assist clinicians working in acute care to determine which stroke and lower limb orthopaedic patients should be discharged to nursing homes, inpatient rehabilitation, or home. The subjects were 223 patients with stroke and 125 patients with lower limb orthopaedic problems, aged 60 years and over, and the 22 acute care and rehabilitation clinicians who cared for these patients. Patient status was measured within 72 hours of discharge using the Adult FIM(SM) (Guide for the Uniform Data Set for Medical Rehabilitation, 1993) and ten additional items from either the RICFAS (Rehabilitation Institute of Chicago, 1987) or developed for this research. Four mathematical models were developed to predict discharge destination using stepwise discriminant function analysis. Using between three and seven items from the FIM(SM) alone or FIM(SM) plus additional variables, these models correctly classified between 74.9% and 80.5% of patients. In conclusion, clinicians are offered a selection of models to guide their discharge destination decisions for two large groups of patients. While these models cannot replace clinical judgement, they increase the transparency of decisions. The use of objective models to guide clinical decisions are essential, particularly given increasing pressure to justify patient access to costly rehabilitation services.

Decision polarization among rehabilitation team recommendations concerning discharge housing for stroke patients.

This study sought to identify if decision polarization effects were operating in rehabilitation teams when making discharge housing recommendations for stroke patients. Using a Social Judgment Theory approach, individual clinicians were asked to nominate discharge housing for stroke patients. Teams were then assembled and clinicians repeated the task. The research was conducted at a sample of seven in-patient rehabilitation hospitals. The subjects were 74 clinicians who formed 13 teams. All subjects were volunteers, and represented the following professions: medicine, nursing, occupational therapy, physical therapy, speech therapy, and social work. A casebook which described 50 hypothetical stroke patients in terms of eight attributes was devised for the study. Subjects made housing recommendations to these patients using a 7-point scale. When compared to individual clinicians' recommendations, it was found that team housing recommendations made by all 13 teams polarized towards both more supported and, in the other extreme, more independent types of housing. However, teams placed a stronger emphasis on supported housing when compared with individual clinician decisions. This decision polarization suggests that housing recommendations made to patients may reflect team processes as well as patient needs. Rehabilitation teams should be aware of this negative team dynamic so that steps to minimize decision polarization can be taken.

Clients' perceptions of discharge housing decisions after stroke rehabilitation.

OBJECTIVE: The purpose of this research was to examine the perceptions of older persons with stroke concerning the discharge housing decisions made during their rehabilitation program. The research explored clients' locus of control, their perceptions of the role of the rehabilitation team and their family in the decision, and their perceptions of their activities of daily living skills. METHOD: Sixty-two subjects with stroke completed four measures: (a) the Functional Independence Measure (FIM), (b) a housing information questionnaire, (c) a semistructured interview, and (d) the Bialer Locus of Control Scale. Rehabilitation team members also completed the FIM and housing information questionnaire for each subject. These instruments were used to collect data relating to clients' perceptions of their functional status, discharge from the hospital, housing options available, and locus of control. RESULTS: Despite the team or family opinions on discharge housing, subjects saw housing decisions as primarily their own. The majority of subjects were reluctant to consider alternatives to returning home, even though they have self-care deficits and frequently reported that the presence of a spouse and family members were important to support their return home. Subjects generally seemed unaware of the influence of team and family opinions and the impact of their functional status on their discharge housing. Subjects' locus of control seemed unrelated to satisfaction with the discharge decision process. CONCLUSION: Clients who have had a stroke could use assistance to determine housing that is appropriate for their living skills. Discussions with clinicians concerning accommodation options may lead to a smoother transition from the hospital to longer term housing for clients after stroke.

Using a head-mounted video camera to study clinical reasoning.

Studies of clinical reasoning are essential if we are to extend our knowledge of occupational therapy practice, better communicate our work to clients and colleagues, and reveal to our students the nuances of therapy that cannot be gained from texts. However, accessing therapists' clinical reasoning is not an easy task because these cognitive processes can be studied only indirectly. The aim of this article is to promote the study of clinical reasoning by reviewing a new approach to data collection in this field. To achieve this purpose, the article outlines current data collection methods, such as the think-aloud method written notes, free recall, and audio-assisted and video-assisted recall. A novel method involving a head-mounted video camera is described, and details are provided on a modified approach to debriefing using video-assisted recall. Anecdotes from the authors experience of using this technology illustrate the text.

Development of an assessment to identify play behaviours that discriminate between the play of typical preschoolers and preschoolers with pre-academic problems.

Occupational therapists regard play as the primary occupation of childhood. However, many authors of play assessments have viewed play either as a functional outcome of other skills or as an indication of the child's developmental level. While such views of play are valid, these approaches to play are broad and do not fully consider the cognitive value of play. A study was undertaken with 82 preschoolers to see if a new play assessment which considers cognitive play skills, called the Child-initiated Pretend Play Assessment, (ChiPPA), possessed acceptable inter-rater reliability, and could discriminate between the play of typically developing preschoolers and preschoolers with pre-academic problems. This assessment evaluates preschoolers' elaborate imaginative actions, number of imitative actions, and number of object substitutions. The ChiPPA was found to have excellent inter-rater reliability and did discriminate between children who were typically developing and children who experienced pre-academic problems. In particular, the elaborateness of a child's play actions and the child's ability to substitute objects were strong discriminators of preschoolers with and without pre-academic problems. Three play profiles which emerged from the research are discussed.

Infra-red laser ablative micromachining of parylene-C on SiO2 substrates for rapid prototyping, high yield, human neuronal cell patterning.

Cell patterning commonly employs photolithographic methods for the micro fabrication of structures on silicon chips. These require expensive photo-mask development and complex photolithographic processing. Laser based patterning of cells has been studied in vitro and laser ablation of polymers is an active area of research promising high aspect ratios. This paper disseminates how 800 nm femtosecond infrared (IR) laser radiation can be successfully used to perform laser ablative micromachining of parylene-C on SiO2 substrates for the patterning of human hNT astrocytes (derived from the human teratocarcinoma cell line (hNT)) whilst 248 nm nanosecond ultra-violet laser radiation produces photo-oxidization of the parylene-C and destroys cell patterning. In this work, we report the laser ablation methods used and the ablation characteristics of parylene-C for IR pulse fluences. Results follow that support the validity of using IR laser ablative micromachining for patterning human hNT astrocytes cells. We disseminate the variation in yield of patterned hNT astrocytes on parylene-C with laser pulse spacing, pulse number, pulse fluence and parylene-C strip width. The findings demonstrate how laser ablative micromachining of parylene-C on SiO2 substrates can offer an accessible alternative for rapid prototyping, high yield cell patterning with broad application to multi-electrode arrays, cellular micro-arrays and microfluidics.

Low cost, patterning of human hNT brain cells on parylene-C with UV & IR laser machining.

This paper describes the use of 800nm femtosecond infrared (IR) and 248nm nanosecond ultraviolet (UV) laser radiation in performing ablative micromachining of parylene-C on SiO2 substrates for the patterning of human hNT astrocytes. Results are presented that support the validity of using IR laser ablative micromachining for patterning human hNT astrocytes cells while UV laser radiation produces photo-oxidation of the parylene-C and destroys cell patterning. The findings demonstrate how IR laser ablative micromachining of parylene-C on SiO2 substrates can offer a low cost, accessible alternative for rapid prototyping, high yield cell patterning.