Effects of primed anodal transcranial direct current stimulation on the psychomotor function of older adults

Declines in cognitive and motor functions as a result of ageing have an adverse impact on the quality of life. One such decline takes the form of poorer psychomotor performance, which involves both cognitive and motor processes in terms of perceiving and processing external stimuli, and executing motor responses. Recent research using transcranial direct current stimulation (tDCS) has shown that priming the corticospinal system by lowering the threshold for the induction of long-term potentiation facilitates subsequent motor performance. Here we utilised this priming approach in a double-blind sham-controlled experiment to investigate the efficacy of the application of tDCS to the dorsolateral prefrontal cortex (DLPFC) in improving the psychomotor performance of older adults. A group of 10 healthy older individuals (mean age 71.60 years; 5 males and 5 females) participated in 2 sessions on separate days, with 1 session involving a 10-minute cathodal tDCS followed by a 20-minute anodal tDCS (C-A), and the other involving a 10-minute cathodal tDCS followed by sham stimulation (C-S) over the left DLPFC. Psychomotor performance was determined through the accuracy and response speeds on a task measuring sustained, selective, and divided attention. The accuracy scores for divided attention were significantly higher in the C-A condition compared with the C-S condition, suggesting that anodal tDCS primed with cathodal tDCS is effective in improving divided attention, and shows promise as a clinical intervention for improving psychomotor function in older adults

Investigating the efficacy of dual-site transcranial alternating current stimulation for alleviating age-related declines in response inhibition

Response inhibition, the ability to suppress or cancel a pre-potent motor action, is instrumental in the flexible adaptation of behaviour to an ever-changing external environment. Unfortunately, inhibitory performance deteriorates with ageing, which is detrimental to the functional independence of older adults. The main objective of this thesis was two-fold. Firstly, to ascertain if age-related declines in response inhibition can be ameliorated by transcranial alternating current stimulation (tACS), a form of non-invasive brain stimulation. Secondly, to gain mechanistic insight into the neurophysiological underpinnings of response inhibition in healthy older individuals. A narrative review (Chapter 1) was conducted to examine the available research evidence on the neural correlates of inhibitory performance. It was found that effective response inhibition performance is subserved by the functional connectivity between the right inferior frontal gyrus (rIFG) and the presupplementary motor area (preSMA), especially for neural activity at beta frequencies. The extant literature also indicates that dual-site tACS can exert facilitatory effects on the functional connectivity between brain regions. Specifically, in-phase tACS, which entails the delivery of currents at the same oscillatory phase to two target sites, was found to promote inter-regional connectivity. Conversely, anti-phase tACS, whereby the currents to the target sites are delivered at opposite phases, was found to weaken interregional connectivity. Therefore, it was deduced that the application of beta frequency inphase tACS over the rIFG and the preSMA could potentially mitigate age-related deficits in inhibitory performance. To test this hypothesis, a double-blind crossover study involving 18 healthy older adults and 15 younger older adults was carried out to elucidate the effects of in- and anti-phase beta tACS (1 mA; 20 min; applied at rest) on stop-signal task performance (Study 1: Chapters 2 to 5). In-phase tACS led to significant improvements in the action cancellation speeds of younger, but not older, individuals. Moreover, in-phase stimulation resulted in a significant brain-behaviour relationship between cancellation speed and resting-state rIFG-preSMA connectivity for younger participants only. The effects of tACS on inhibitory performance appeared to be contingent upon the endogenous beta-band phase angle difference between rIFG and preSMA during resting-state. Anti-phase tACS was also found to exert differential effects on cortico-cortical gamma-band coupling for older and younger individuals. However, these age-related differences in network connectivity were not reflected in inhibitory performance. tACS-induced changes in response inhibition performance also appeared to be independent of task-related rIFG-preSMA phase connectivity on the scalp- and cortical-level for both older and younger adults. A substantial inter-individual variability in tACS-induced neurophysiological outcomes was also detected, particularly for older participants. This suggests that there may be greater heterogeneity in the dose-response relationship of older adults, in comparison to their younger counterparts. Subsequently, electric field simulation modelling was conducted to explore how the current dosage of the dual-site tACS protocol could be modified to improve the intensity and focality of tACS-induced currents in the brain (Study 2: Chapter 6). It was found that higher field strengths are accompanied by poorer field focality to target sites, and that this strengthfocality trade-off must be considered when deciding on tACS current intensities. The current dosages of the tACS protocol utilised in Study 1 were revised in consideration of the findings of Study 2. A sham-controlled, double-blind, crossover study was conducted to test the efficacy of this modified tACS protocol (1.0 mA for rIFG, 1.6 mA for preSMA; 20 min) on improving the inhibitory performance of seven healthy older adults (Study 3: Chapter 7). The study also investigated if an ‘online’ approach, where tACS was administered during task performance, would be more efficacious than if tACS was applied ‘offline’, i.e., when participants were at rest and in a task-free state. Due to the small sample size, group-level and single-subject analyses were employed. The findings of Study 3 indicated that neither online nor offline tACS significantly improved stop-signal task performance. Furthermore, not only was cancellation speed not associated with beta-band phase-coupling between rIFG and preSMA during resting-state and task performance, their inter-regional phase connectivity was not a significant predictor of stop outcome, i.e., the success or failure of stop attempts. Instead, task-related gamma-band rIFG-preSMA phase-coupling was found to be a significant predictor of stop outcome. Changes in source-reconstructed cortio-cortical networks from pre- to post-sham stimulation were also indicative of potential fatigue-related changes in network connections – this is an important factor that future research will need to account for when studying tACS-induced changes in phase-coupling during task performance. Overall, the findings of this thesis suggest that rIFG-preSMA beta tACS was potentially efficacious in facilitating the inhibitory performance of healthy younger adults. However, its effects in healthy older individuals were subject to considerable heterogeneity. Despite the lack of clear evidence supporting the efficacy of this tACS protocol in alleviating age-related declines in response inhibition, the findings of this thesis have provided important insights into the neural underpinnings of inhibitory performance and contributed to a broader mechanistic understanding of the effects of dual-site tACS on functional connectivity

The Ingenuity of Everyday Practice: A Framework for Justice-Centered Identity Work in Engineering in the Middle Grades

Inequities in opportunities to learn and become in engineering, especially for minoritized youth, are enduring and systemic. How students experience engineering education, through curriculum, pedagogy, and teacher/student interactions, all shape opportunities for identity development. In this paper we draw upon cultural studies and critical ethnography to explore how and why students engage in engineering for sustainable communities and its relationship to their identity work. We ground our work in a justice-centered asset-based stance that centers how people’s lived lives and community wisdom yield powerful forms of cultural knowledge/practice relevant to learning and engaging in science, technology, engineering, and mathematics. We seek to accentuate students’ ingenuity to leverage their assets for social change making; that is, in transformative and future-oriented ways. We view youths’ everyday ingenuity as powerful assets for learning and participating in authentic engineering design for sustainable communities. Findings suggest that engineering for sustainable communities created opportunities for productive identity work because it created space for youth to authentically engage in engineering design in ways that allowed them to care about each other, their classroom and community, and to use both their everyday ingenuity and technical expertise to make a difference. We also suggest that students’ identity work took shape through the emergence of new local contentious practices of engineering for sustainable communities that both amplified youths’ ingenuity and challenged particular local, historical/sociocultural norms of engineering and schooling. These contentious local practices related to disrupting the authority to name what counts as engineering problems worth solving and disrupting narratives around what it means to persist through iterations in design. We suggest that an engineering for sustainable communities approach supports the production of local and productive contentious practice because it centers community co-ownership in the design, and supports students in leveraging their everyday ingenuity as critical knowhow in engineering design

A Case of Lung Cancer with Isolated Skip Metastasis to an External Iliac Lymph Node

Introduction: Isolated skip metastases to intra-abdominal lymph nodes from lung cancer are rare and management of such disease remains controversial.  Presentation of case: We report a case of lung adenocarcinoma in the right upper lobe with isolated lymph node metastasis to an external iliac lymph node detected by Positron Emission Tomography (PET) scan which was confirmed histopathologically.  Conclusion: Isolated intra-abdominal lymph nodes from lung cancer are a rare occurrence.  In these patients, lymphadenectomy can be considered together with definitive treatment of the lung primary

A qualitative document analysis of policies influencing preeclampsia management by midwives in Ghana

Background: Preeclampsia is a global issue that causes significant morbidity and mortality in low- and middle-income countries (LMICs). The care women with preeclampsia receive in LMICs is below the standard experienced by women in westernised countries due to multiple interacting factors. A review of policy factors influencing the management of preeclampsia in Ghana is needed. Aim: This study focuses on the midwife\u27s role and scope of practice concerning preeclampsia management. The study aimed to explore the congruence between Ghanaian preeclampsia guidelines and international best practice recommendations for midwifery practice. The study also aimed to describe how recommendations are incorporated into Ghanaian guidelines. Method/design: This study was a qualitative document analysis of national and tertiary hospital policies related to midwives’ scope of practice in Ghana. Altheide\u27s five-step process (sampling, data collection, data coding and organisation, data analysis and report) was used to systematically source and analyse the content of written documents. Results: The findings illustrated several recommendation shortcomings in Ghanaian documents at the national and tertiary hospital levels. The content of Ghanaian preeclampsia management guidelines was not comprehensive, contained conflicting information, and was not backed by research evidence. The standards of practice for midwives were consistent at both the national and tertiary hospital levels. Midwives had limited roles in detection, management, stabilisation, and referral of women with preeclampsia. Conclusion: Uniform guidelines incorporating international recommendations are urgently needed to improve multi-professional collaboration, solidify midwives’ roles, and optimise maternal and fetal outcomes

Which Factors Determine User’s First and Repeat Online Music Listening Respectively? Music Itself, User Itself, or Online Feedback

In the era of Web 2.0, does online feedback mainly dominant online users’ buying behavior, or are user’s own preference and product quality still important? Previous studies paid more attention to the influence of online feedback on users’ online buying behavior, however this paper focuses on how users’ own factors, product quality related factors and online feedback factors together influence a user’s buying behavior, and also how does this effect change as time goes by. Taking online music as our research industry and using the data from Last.fm website, this research shows that users’ preference and product quality are still the two most dominate factors influencing users’ online music listening, while online feedback plays an important role on users’ first listening. It is also found that the different influences of crowds and friends

Effect of phase separation and supercooling on the storage capacity in a commercial latent heat thermal energy storage: Experimental cycling of a salt hydrate PCM

Latent heat storage technologies offer process benefits like daily peak shaving. In this work a commercial storage design for storing cold thermal energy has been studied using a laboratory prototype containing 168 kg of a commercial salt-hydrate phase change material (PCM). The storage was charged and discharged with subsequent cycles at different mass flow rates over a fixed temperature range and duration. It was found that the PCM TES design exhibits phase separation and increased supercooling with continuous cycling. Both phenomena lead to a gradual decrease of the effective storage capacity. With later cycles only the bottom part stores latent heat, while the top and middle parts of the storage remain liquid. The results were repeatable and are consistent with T-History measurements of samples from the PCM TES before and after cycling. It is likely that the PCM itself does not suffer from incongruent melting. Instead, the phase separation is likely to occur due to a segregation of different liquid phases across the height of the storage. It was found that T-History measurements alone are not able to predict this behavior. Moreover, it is shown that phase separation in the storage can be reversed by increasing the PCM temperature and mechanical mixing of the liquid phase. This phase separation has to be prevented in future work in order to achieve stable performance with the studied storage design

Detection of NPM1 exon 12 mutations and FLT3 – internal tandem duplications by high resolution melting analysis in normal karyotype acute myeloid leukemia

<p>Abstract</p> <p>Background</p> <p>Molecular characterisation of normal karyotype acute myeloid leukemia (NK-AML) allows prognostic stratification and potentially can alter treatment choices and pathways. Approximately 45–60% of patients with NK-AML carry <it>NPM1 </it>gene mutations and are associated with a favourable clinical outcome when <it>FLT3</it>-internal tandem duplications (ITD) are absent. High resolution melting (HRM) is a novel screening method that enables rapid identification of mutation positive DNA samples.</p> <p>Results</p> <p>We developed HRM assays to detect <it>NPM1 </it>mutations and <it>FLT3</it>-ITD and tested diagnostic samples from 44 NK-AML patients. Eight were <it>NPM1 </it>mutation positive only, 4 were both <it>NPM1 </it>mutation and <it>FLT3</it>-ITD positive and 4 were <it>FLT3</it>-ITD positive only. A novel point mutation Y572C (c.1715A>G) in exon 14 of <it>FLT3 </it>was also detected. In the group with <it>de novo </it>NK-AML, 40% (12/29) were <it>NPM1 </it>mutation positive whereas <it>NPM1 </it>mutations were observed in 20% (3/15) of secondary NK-AML cases. Sequencing was performed and demonstrated 100% concordance with the HRM results.</p> <p>Conclusion</p> <p>HRM is a rapid and efficient method of screening NK-AML samples for both novel and known <it>NPM1 </it>and <it>FLT3 </it>mutations. <it>NPM1 </it>mutations can be observed in both primary and secondary NK-AML cases.</p