Measurement of ventilation and cardiac related impedance changes with electrical impedance tomography

Introduction Electrical impedance tomography (EIT) has been shown to be able to distinguish both ventilation and perfusion. With adequate filtering the regional distributions of both ventilation and perfusion and their relationships could be analysed. Several methods of separation have been suggested previously, including breath holding, electrocardiograph (ECG) gating and frequency filtering. Many of these methods require interventions inappropriate in a clinical setting. This study therefore aims to extend a previously reported frequency filtering technique to a spontaneously breathing cohort and assess the regional distributions of ventilation and perfusion and their relationship. Methods Ten healthy adults were measured during a breath hold and while spontaneously breathing in supine, prone, left and right lateral positions. EIT data were analysed with and without filtering at the respiratory and heart rate. Profiles of ventilation, perfusion and ventilation/perfusion related impedance change were generated and regions of ventilation and pulmonary perfusion were identified and compared. Results Analysis of the filtration technique demonstrated its ability to separate the ventilation and cardiac related impedance signals without negative impact. It was, therefore, deemed suitable for use in this spontaneously breathing cohort. Regional distributions of ventilation, perfusion and the combined ΔZV/ΔZQ were calculated along the gravity axis and anatomically in each position. Along the gravity axis, gravity dependence was seen only in the lateral positions in ventilation distribution, with the dependent lung being better ventilated regardless of position. This gravity dependence was not seen in perfusion. When looking anatomically, differences were only apparent in the lateral positions. The lateral position ventilation distributions showed a difference in the left lung, with the right lung maintaining a similar distribution in both lateral positions. This is likely caused by more pronounced anatomical changes in the left lung when changing positions. Conclusions The modified filtration technique was demonstrated to be effective in separating the ventilation and perfusion signals in spontaneously breathing subjects. Gravity dependence was seen only in ventilation distribution in the left lung in lateral positions, suggesting gravity based shifts in anatomical structures. Gravity dependence was not seen in any perfusion distributions.

Single-subject analysis reveals varied knee mechanics during step landing in response to isokinetic fatigue of the quadriceps

Introduction: The ability to regulate joint stiffness and coordinate movement during landing when impaired by muscle fatigue has important implications for knee function. Unfortunately, the literature examining fatigue effects on landing mechanics suffers from a lack of consensus. Inconsistent results can be attributed to variable fatigue models, as well as grouping variable responses between individuals when statistically detecting differences between conditions. There remains a need to examine fatigue effects on knee function during landing with attention to these methodological limitations. Aim: The purpose of this study therefore, was to examine the effects of isokinetic fatigue on pre-impact muscle activity and post-impact knee mechanics during landing using singlesubject analysis. Methodology: Sixteen male university students (22.6+3.2 yrs; 1.78+0.07 m; 75.7+6.3 kg) performed maximal concentric and eccentric knee extensions in a reciprocal manner on an isokinetic dynamometer and step-landing trials on 2 occasions. On the first occasion each participant performed 20 step-landing trials from a knee-high platform followed by 75 maximal contractions on the isokinetic dynamometer. The isokinetic data was used to calculate the operational definition of fatigue. On the second occasion, with a minimum rest of 14 days, participants performed 2 sets of 20 step landing trials, followed by isokinetic exercise until the operational definition of fatigue was met and a final post-fatigue set of 20 step-landing trials. Results: Single-subject analyses revealed that isokinetic fatigue of the quadriceps induced variable responses in pre impact activation of knee extensors and flexors (frequency, onset timing and amplitude) and post-impact knee mechanics(stiffness and coordination). In general however, isokinetic fatigue induced sig nificant (p<0.05) reductions in quadriceps activation frequency, delayed onset and increased amplitude. In addition, knee stiffness was significantly (p<0.05) increased in some individuals, as well as impaired sagittal coordination. Conclusions: Pre impact activation and post-impact mechanics were adjusted in patterns that were unique to the individual, which could not be identified using traditional group-based statistical analysis. The results suggested that individuals optimised knee function differently to satisfy competing demands, such as minimising energy expenditure, as well as maximising joint stability and sensory information.

Single-subject analysis reveals variation in knee mechanics during step landing

Introduction: Evidence concerning the alteration of knee function during landing suffers from a lack of consensus. This uncertainty can be attributed to methodological flaws, particularly in relation to the statistical analysis of variable human movement data. Aim: The aim of this study was to compare single-subject and group analysis in quantifying alterations in the magnitude and within-participant variability of knee mechanics during a step landing task. Methods: A group of healthy men (N = 12) stepped-down from a knee-high platform for 60 consecutive trials, each trial separated by a 1-minute rest. The magnitude and within-participant variability of sagittal knee stiffness and coordination of the landing leg during the immediate postimpact period were evaluated. Coordination of the knee was quantified in the sagittal plane by calculating the mean absolute relative phase of sagittal shank and thigh motion (MARP1) and between knee rotation and knee flexion (MARP2). Changes across trials were compared between both group and single-subject statistical analyses. Results: The group analysis detected significant reductions in MARP1 magnitude. However, the single-subject analyses detected changes in all dependent variables, which included increases in variability with task repetition. Between-individual variation was also present in the timing, size and direction of alterations to task repetition. Conclusion: The results have important implications for the interpretation of existing information regarding the adaptation of knee mechanics to interventions such as fatigue, footwear or landing height. It is proposed that a familiarisation session be incorporated in future experiments on a single-subject basis prior to an intervention.

Spelling instruction through Etymology : a method of developing spelling lists for older students

The purpose of this study was to investigate whether an approach to developing word lists centred on etymological roots would improve the spelling performance of older primary school students. Participants were 46 students in the last year of primary school in south-east Queensland (31 girls and 15 boys) across three classes, with two classes being assigned to control conditions. Students were evaluated pre- and post-intervention on three dependent measures: British Spelling Test Series spelling, spelling in writing and writing. The results of this intervention revealed improvements in spelling for girls but not for boys. The implications for improved teaching methods are discussed.

Understanding teachers' reporting of child sexual abuse : measurement methods matter

The present study considered factors influencing teachers' reporting of child sexual abuse (CSA). Conducted in three Australian jurisdictions with different reporting laws and policies, the study focused on teachers' actual past and anticipated future reporting of CSA. A sample of 470 teachers within randomly selected rural and urban schools was surveyed, to identify training and experience; knowledge of reporting legislation and policy; attitudes; and reporting practices. Factors influencing actual past reporting and anticipated future reporting were identified using logistic regression modelling. This is the first study to simultaneously examine the effect of important influences in reporting practice using both retrospective and prospective approaches across jurisdictions with different reporting laws. Teachers who have actually reported CSA in the past are more likely have higher levels of policy knowledge, and hold more positive attitudes towards reporting CSA along three specific dimensions: commitment to the reporting role; confidence in the system's effective response to their reporting; and they are more likely to be able to override their concerns about the consequences of their reporting. Teachers indicating intention to report hypothetical scenarios are more likely to hold reasonable grounds for suspecting CSA, to recognise that significant harm has been caused to the child, to know that their school policy requires a report, and to be able to override their concerns about the consequences of their reporting.

Victims’ perceptions of traditional and cyberbullying, and the psychosocial correlates of their victimisation

It is well recognised that there are serious correlates for victims of traditional bullying. These have been shown to include increased levels of depression, anxiety and psychosomatic symptoms, in addition to often severe physical harm and even suicide. Bullied students also feel more socially ineffective; have greater interpersonal difficulties, together with higher absenteeism from school and lower academic competence. In the emerging field of cyberbullying many researchers have hypothesised a greater impact and more severe consequences for victims because of the 24/7 nature and the possibility of the wider audience with this form of bullying. However, to date there is scarce empirical evidence to support this. This study sought to compare victims’ perceptions of the harshness and impact of bullying by traditional and cyber means. The major findings showed that although students who had been victimised by traditional bullying reported that they felt their bullying was harsher, crueller and had more impact on their lives than those students who had been cyberbullied, the correlates of their mental health revealed that cyber victims reported significantly more social difficulties, higher anxiety levels and depression than traditional victims. The implications for school counsellors and mental health workers are discussed.

How research findings can inform legislation and school policy on cyberbullying.

Recent empirical research has found that the psychological consequences for young people involved in cyberbullying are more severe than in the case of traditional bullying (Campbell, Spears, Slee, Butler, & Kift, 2012; Perren, Dooley, Shaw, & Cross, 2010). Cybervictimisation has been found to be a significant predictor of depressive symptoms over and above that of being victimised by traditional bullying (Perren et al., 2010). Cybervictims also have reported higher anxiety scores and social difficulties than traditional victims, with those students who had been bullied by both forms showing similar anxiety and depression scores to cyberbullying victims (Campbell et al., 2012). This is supported by the subjective views of many young people, not involved in bullying, who believed that cyberbullying is far more harmful than traditional bullying (Cross et al., 2009). However, students who were traditionally bullied thought the consequences of traditional bullying were harsher than did those students who were cyberbullied (Campbell, et al., 2012). In Slonje and Smith’s study (2008), students reported that text messaging and email bullying had less of an impact than traditional bullying, but that bullying by pictures or video clips had more negative impact than traditional bullying.

Phenotypic Characterization of Prostate Cancer LNCaP Cells Cultured within a Bioengineered Microenvironment

Biophysical and biochemical properties of the microenvironment regulate cellular responses such as growth, differentiation, morphogenesis and migration in normal and cancer cells. Since two-dimensional (2D) cultures lack the essential characteristics of the native cellular microenvironment, three-dimensional (3D) cultures have been developed to better mimic the natural extracellular matrix. To date, 3D culture systems have relied mostly on collagen and Matrigel™ hydrogels, allowing only limited control over matrix stiffness, proteolytic degradability, and ligand density. In contrast, bioengineered hydrogels allow us to independently tune and systematically investigate the influence of these parameters on cell growth and differentiation. In this study, polyethylene glycol (PEG) hydrogels, functionalized with the Arginine-glycine-aspartic acid (RGD) motifs, common cell-binding motifs in extracellular matrix proteins, and matrix metalloproteinase (MMP) cleavage sites, were characterized regarding their stiffness, diffusive properties, and ability to support growth of androgen-dependent LNCaP prostate cancer cells. We found that the mechanical properties modulated the growth kinetics of LNCaP cells in the PEG hydrogel. At culture periods of 28 days, LNCaP cells underwent morphogenic changes, forming tumor-like structures in 3D culture, with hypoxic and apoptotic cores. We further compared protein and gene expression levels between 3D and 2D cultures upon stimulation with the synthetic androgen R1881. Interestingly, the kinetics of R1881 stimulated androgen receptor (AR) nuclear translocation differed between 2D and 3D cultures when observed by immunofluorescent staining. Furthermore, microarray studies revealed that changes in expression levels of androgen responsive genes upon R1881 treatment differed greatly between 2D and 3D cultures. Taken together, culturing LNCaP cells in the tunable PEG hydrogels reveals differences in the cellular responses to androgen stimulation between the 2D and 3D environments. Therefore, we suggest that the presented 3D culture system represents a powerful tool for high throughput prostate cancer drug testing that recapitulates tumor microenvironment. © 2012 Sieh et al.

Exploratory factor analysis and psychometric evaluation of the Teachers Reporting Attitude Scale for Child Sexual Abuse

This paper presents an evaluation of an instrument to measure teachers’ attitudes towards reporting child sexual abuse and discusses the instrument’s merit for research into reporting practice. Based on responses from 444 Australian teachers, the Teachers’ Reporting Attitude Scale for Child Sexual Abuse (TRAS - CSA) was evaluated using exploratory factor analysis. The scale isolated three dimensions: commitment to the reporting role; confidence in the system’s response to reports; and concerns about reporting. These three factors accounted for 37.5% of the variance in the 14-item measure. Alpha coefficients for the subscales were 0.769 (commitment), 0.617 (confidence), and 0.661 (concerns). The findings provide insights into the complexity of studying teachers’ attitudes towards reporting of child sexual abuse, and have implications for future research.

Sustaining the future through virtual worlds

Virtual worlds (VWs) continue to be used extensively in Australia and New Zealand higher education institutions although the tendency towards making unrealistic claims of efficacy and popularity appears to be over. Some educators at higher education institutions continue to use VWs in the same way as they have done in the past; others are exploring a range of different VWs or using them in new ways; whilst some are opting out altogether. This paper presents an overview of how 46 educators from some 26 institutions see VWs as an opportunity to sustain higher education. The positives and negatives of using VWs are discussed.