title: Dynamics of immobilized and native Escherichia coli dihydrofolate reductase by quasielastic neutron scattering

authors: Tehei, Moeava

abstract: The internal dynamics of native and immobilized Escherichia coli dihydrofolate reductase (DHFR) have been examined using incoherent quasielastic neutron scattering. These results reveal no difference between the high frequency vibration mean-square displacement of the native and the immobilized E. coli DHFR. However, length-scale-dependent, picosecond dynamical changes are found. On longer length scales, the dynamics are comparable for both DHFR samples. On shorter length scales, the dynamics is dominated by local jump motions over potential barriers. The residence time for the protons to stay in a potential well is  = 7.95 ± 1.02 ps for the native DHFR and  = 20.36 ± 1.80 ps for the immobilized DHFR. The average height of the potential barrier to the local motions is increased in the immobilized DHFR, and may increase the activation energy for the activity reaction, decreasing the rate as observed experimentally. These results suggest that the local motions on the picosecond timescale may act as a lubricant for those associated with DHFR activity occurring on a slower millisecond timescale. Experiments indicate a significantly slower catalytic reaction rate for the immobilized E. coli DHFR. However, the immobilization of the DHFR is on the exterior of the enzyme and essentially distal to the active site, thus this phenomenon has broad implications for the action of drugs distal to the active site.

text: Dynamics of immobilized and native Escherichia coli dihydrofolate reductase by quasielastic neutron scattering The internal dynamics of native and immobilized Escherichia coli dihydrofolate reductase (DHFR) have been examined using incoherent quasielastic neutron scattering. These results reveal no difference between the high frequency vibration mean-square displacement of the native and the immobilized E. coli DHFR. However, length-scale-dependent, picosecond dynamical changes are found. On longer length scales, the dynamics are comparable for both DHFR samples. On shorter length scales, the dynamics is dominated by local jump motions over potential barriers. The residence time for the protons to stay in a potential well is  = 7.95 ± 1.02 ps for the native DHFR and  = 20.36 ± 1.80 ps for the immobilized DHFR. The average height of the potential barrier to the local motions is increased in the immobilized DHFR, and may increase the activation energy for the activity reaction, decreasing the rate as observed experimentally. These results suggest that the local motions on the picosecond timescale may act as a lubricant for those associated with DHFR activity occurring on a slower millisecond timescale. Experiments indicate a significantly slower catalytic reaction rate for the immobilized E. coli DHFR. However, the immobilization of the DHFR is on the exterior of the enzyme and essentially distal to the active site, thus this phenomenon has broad implications for the action of drugs distal to the active site.

year: 2006-10

title: Servant leadership and work engagement: The mediating role of work-life balance

authors: Haar, Jarrod M.

abstract: While the effect of leadership is established, the influence and process towards work engagement is under researched. This is particularly true of servant leadership, despite the links suggesting followers of such leaders are likely to be more engaged. The present study tests servant leadership towards the three dimensions of work engagement: (1) vigour, (2) dedication and (3) absorption. In addition, we test the role of work-life balance as a potential mediator, to test whether servant leadership builds work-life balance, which ultimately leads to higher work engagement. The present study is based on a sample of 123 New Zealand employees from a wide range of professions. Using structural equation modelling we test a number of path models to determine the best fit to the data, with the best fitting model being a full mediation model. Overall, we find strong support for servant leadership predicting work-life balance and the three work engagement dimensions. However, the influence of servant leadership is fully mediated by work-life balance. Ultimately work-life balance is positively related to all three work engagement dimensions and fully mediates the effect of servant leadership, highlighting the important role that work-life balance may play in achieving higher work engagement. The implications for human resource management (HRM) are discussed.

text: Servant leadership and work engagement: The mediating role of work-life balance While the effect of leadership is established, the influence and process towards work engagement is under researched. This is particularly true of servant leadership, despite the links suggesting followers of such leaders are likely to be more engaged. The present study tests servant leadership towards the three dimensions of work engagement: (1) vigour, (2) dedication and (3) absorption. In addition, we test the role of work-life balance as a potential mediator, to test whether servant leadership builds work-life balance, which ultimately leads to higher work engagement. The present study is based on a sample of 123 New Zealand employees from a wide range of professions. Using structural equation modelling we test a number of path models to determine the best fit to the data, with the best fitting model being a full mediation model. Overall, we find strong support for servant leadership predicting work-life balance and the three work engagement dimensions. However, the influence of servant leadership is fully mediated by work-life balance. Ultimately work-life balance is positively related to all three work engagement dimensions and fully mediates the effect of servant leadership, highlighting the important role that work-life balance may play in achieving higher work engagement. The implications for human resource management (HRM) are discussed.

year: 2017

title: Evaluation of treatment responsivity in a psychopathic prison treatment sample

authors: Champion, Michelle Elizabeth

subjects: psychopathy

abstract: Although punishment still dominates the criminal justice system, the progression of research on offending and imprisonment has led to a general consensus that rehabilitation programmes are the appropriate method to effectively reduce both recidivism and prison populations. Hence, many effective offender treatment programmes have been developed. This thesis evaluated phase one of a 10 month pilot treatment programme which used the theories and principles of effective programming to develop an effective programme for male high risk violent offenders assessed with elevated psychopathic personality (High Risk Personality Programme; HRPP), a population of offenders that is often regarded as treatment resistant. Specifically, phase one of the HRPP was designed to address the participants’ responsivity barriers (namely, antisocial interpersonal style) in order to increase self-efficacy, therapeutic alliance, treatability, and readiness, and to reduce perceived coercion in order to aid engagement and success in treatment. A sample of 11 male HRPP inmates had data collected before and after their 17-week first phase of the 10 month three-phase programme. Treatment contact comprised four sessions per week, including three group sessions of 2.5 hours, and 1 individual session of one hour, as well as a two-hour group cultural session that focused on Maori cultural identity (10 of the 11 men were Maori). The battery of tests employed included the Self-Efficacy Questionnaire; the responsivity and readiness scales of the Treatment Readiness Responsivity and Gain Scale; the Corrections Victoria Treatment Readiness Questionnaire, the Paulhus Deception Scale, and the therapist and client versions of the Working Alliance Inventory Short Form, the Perceived Coercion Scale, and an evaluation questionnaire. Demographic data was also collected. The results indicated that the majority of the participants came to the intervention ready or motivated to change. Perceived coercion remained low throughout the programme, representing the participant’s voluntary status. On average participants’ levels of self-efficacy and treatability (except callousness) improved significantly over the course of the treatment. Differing levels of improvement were found for the client and therapist perspective of the therapeutic alliance, indicating they interpreted the alliance differently. Participants with high PCL-R factor one scores showed a decrease in coercion, compared to an increase by their counterparts with low PCL-R factor one scores. Participants with high PCL-R factor one scores also had higher overall scores on the CVTRQ readiness measure, and the participant’s perspective of the therapeutic alliance. Individually, six of the treatment participants made significant improvements on at least five of the seven responsivity measures. These findings and their implications for treatment of psychopathic offenders are discussed, along with the relevance of the study’s responsivity measures, the strengths and limitations of the research project, and future research in this area.

text: Evaluation of treatment responsivity in a psychopathic prison treatment sample Although punishment still dominates the criminal justice system, the progression of research on offending and imprisonment has led to a general consensus that rehabilitation programmes are the appropriate method to effectively reduce both recidivism and prison populations. Hence, many effective offender treatment programmes have been developed. This thesis evaluated phase one of a 10 month pilot treatment programme which used the theories and principles of effective programming to develop an effective programme for male high risk violent offenders assessed with elevated psychopathic personality (High Risk Personality Programme; HRPP), a population of offenders that is often regarded as treatment resistant. Specifically, phase one of the HRPP was designed to address the participants’ responsivity barriers (namely, antisocial interpersonal style) in order to increase self-efficacy, therapeutic alliance, treatability, and readiness, and to reduce perceived coercion in order to aid engagement and success in treatment. A sample of 11 male HRPP inmates had data collected before and after their 17-week first phase of the 10 month three-phase programme. Treatment contact comprised four sessions per week, including three group sessions of 2.5 hours, and 1 individual session of one hour, as well as a two-hour group cultural session that focused on Maori cultural identity (10 of the 11 men were Maori). The battery of tests employed included the Self-Efficacy Questionnaire; the responsivity and readiness scales of the Treatment Readiness Responsivity and Gain Scale; the Corrections Victoria Treatment Readiness Questionnaire, the Paulhus Deception Scale, and the therapist and client versions of the Working Alliance Inventory Short Form, the Perceived Coercion Scale, and an evaluation questionnaire. Demographic data was also collected. The results indicated that the majority of the participants came to the intervention ready or motivated to change. Perceived coercion remained low throughout the programme, representing the participant’s voluntary status. On average participants’ levels of self-efficacy and treatability (except callousness) improved significantly over the course of the treatment. Differing levels of improvement were found for the client and therapist perspective of the therapeutic alliance, indicating they interpreted the alliance differently. Participants with high PCL-R factor one scores showed a decrease in coercion, compared to an increase by their counterparts with low PCL-R factor one scores. Participants with high PCL-R factor one scores also had higher overall scores on the CVTRQ readiness measure, and the participant’s perspective of the therapeutic alliance. Individually, six of the treatment participants made significant improvements on at least five of the seven responsivity measures. These findings and their implications for treatment of psychopathic offenders are discussed, along with the relevance of the study’s responsivity measures, the strengths and limitations of the research project, and future research in this area.

year: 2010