Two Dimensional Bistable Vibration Energy Harvester

n/

Magnetically-Coupled Cantilevers with Antiphase Bistable Behavior for Kinetic Energy Harvesting

n/

“Having diabetes shouldn’t stop them”: healthcare professionals’ perceptions of physical activity in children with Type 1 diabetes

Background Healthcare professionals (HCP) working with children who have Type 1 Diabetes Mellitus (T1DM) have an important role in advising about and supporting the control of blood glucose level in relation to physical activity. Regular physical activity has known benefits for children with T1DM, but children with chronic conditions may face barriers to participation. The perceptions of HCPs were explored in an effort to understand what influences physical activity in children with T1DM and to inform the practice of those working with children who have T1DM. Methods Semi-structured interviews with 11 HCPs involved in the care of children with T1DM in the UK were conducted. Interviews were recorded, transcribed verbatim and data were analysed using thematic analysis. Results The factors perceived to influence participation in physical activity are presented as five major themes and eleven sub-themes. Themes included the positive influence of social support, the child’s motivation to be active, the potential for formal organisations such as school and diabetes clinic to support physical activity, the challenges faced by those who have T1DM and the perceived barriers to HCPs fulfilling their role of promoting physical activity. Conclusions Healthcare professionals recognised their role in helping children with T1DM and their parents to incorporate physical activity into diabetes management and everyday life, but perceived barriers to the successful fulfilment of this role. The findings highlight the potential for clinical and non-clinical supportive systems to be sensitive to these challenges and facilitate children’s regular participation in physical activity

A physical activity intervention for children with type 1 diabetes- steps to active kids with diabetes (STAK-D): a feasibility study

Background This study describes the development and feasibility evaluation of a physical activity intervention for children with type 1 diabetes called ‘Steps to Active Kids with Diabetes’ (STAK-D). It aims to explore the feasibility and acceptability of the intervention and study design. Methods Thirteen children aged 9-11 years and their parents were recruited from one paediatric diabetes clinic. A process evaluation was conducted alongside a two-arm randomised feasibility trial, including assessment of rate of recruitment, adherence, retention, data completion and burden, implementation fidelity and adverse events. Qualitative interviews with children (n=9), parents (n=8), healthcare professionals (n=3) and STAK-D volunteers (n=8) explored intervention acceptability. Interviews were analysed thematically. Results Rate of recruitment was 25%, with 77% retention at 3-month follow-up. Study burden was low, data completion was high and the intervention was delivered as per protocol. No serious adverse event was reported. Engagement with intervention materials was generally good, but attendance at group activity sessions was low due to logistical barriers. Interview analysis identified preferred methods of recruitment, motivations for recruitment, barriers and facilitators to adherence, the experience of data collection, experience of the STAK-D programme and its perceived benefits. Conclusions STAK-D was feasible and acceptable to children, their parents and healthcare professionals, but group sessions may present logistical issues. Recruitment and retention may be improved with a clinic-wide approach to recruitment. Trial registration This trial was registered on ClinicalTrials.gov: NCT02144337 (16/01/2014). Keywords Children, feasibility study, intervention, paediatric diabetes, physical activity, process evaluation, self-efficacy, type 1 diabete

Cell Death by SecTRAPs: Thioredoxin Reductase as a Prooxidant Killer of Cells

BACKGROUND: SecTRAPs (selenium compromised thioredoxin reductase-derived apoptotic proteins) can be formed from the selenoprotein thioredoxin reductase (TrxR) by targeting of its selenocysteine (Sec) residue with electrophiles, or by its removal through C-terminal truncation. SecTRAPs are devoid of thioredoxin reductase activity but can induce rapid cell death in cultured cancer cell lines by a gain of function. PRINCIPAL FINDINGS: Both human and rat SecTRAPs killed human A549 and HeLa cells. The cell death displayed both apoptotic and necrotic features. It did not require novel protein synthesis nor did it show extensive nuclear fragmentation, but it was attenuated by use of caspase inhibitors. The redox active disulfide/dithiol motif in the N-terminal domain of TrxR had to be maintained for manifestation of SecTRAP cytotoxicity. Stopped-flow kinetics showed that NADPH can reduce the FAD moiety in SecTRAPs at similar rates as in native TrxR and purified SecTRAPs could maintain NADPH oxidase activity, which was accelerated by low molecular weight substrates such as juglone. In a cellular context, SecTRAPs triggered extensive formation of reactive oxygen species (ROS) and consequently antioxidants could protect against the cell killing by SecTRAPs. CONCLUSIONS: We conclude that formation of SecTRAPs could contribute to the cytotoxicity seen upon exposure of cells to electrophilic agents targeting TrxR. SecTRAPs are prooxidant killers of cells, triggering mechanisms beyond those of a mere loss of thioredoxin reductase activity

Accelerometer Measured Levels of Moderate-to-Vigorous Intensity Physical Activity and Sedentary Time in Children and Adolescents with Chronic Disease: a Systematic Review and Meta-Analysis

Context: Moderate-to-vigorous physical activity (MVPA) and sedentary time (ST) are important for child and adolescent health. Objective: To examine habitual levels of accelerometer measured MVPA and ST in children and adolescents with chronic disease, and how these levels compare with healthy peers. Methods: Data sources: An extensive search was carried out in Medline, Cochrane library, EMBASE, SPORTDiscus and CINAHL from 2000–2017. Study selection: Studies with accelerometer-measured MVPA and/or ST (at least 3 days and 6 hours/day to provide estimates of habitual levels) in children 0–19 years of age with chronic diseases but without co-morbidities that would present major impediments to physical activity. In all cases patients were studied while well and clinically stable. Results: Out of 1592 records, 25 studies were eligible, in four chronic disease categories: cardiovascular disease (7 studies), respiratory disease (7 studies), diabetes (8 studies), and malignancy (3 studies). Patient MVPA was generally below the recommended 60 min/day and ST generally high regardless of the disease condition. Comparison with healthy controls suggested no marked differences in MVPA between controls and patients with cardiovascular disease (1 study, n = 42) and type 1 diabetes (5 studies, n = 400; SMD -0.70, 95% CI -1.89 to 0.48, p = 0.25). In patients with respiratory disease, MVPA was lower in patients than controls (4 studies, n = 470; SMD -0.39, 95% CI -0.80, 0.02, p = 0.06). Meta-analysis indicated significantly lower MVPA in patients with malignancies than in the controls (2 studies, n = 90; SMD -2.2, 95% CI -4.08 to -0.26, p = 0.03). Time spent sedentary was significantly higher in patients in 4/10 studies compared with healthy control groups, significantly lower in 1 study, while 5 studies showed no significant group difference. Conclusions: MVPA in children/adolescents with chronic disease appear to be well below guideline recommendations, although comparable with activity levels of their healthy peers except for children with malignancies. Tailored and disease appropriate intervention strategies may be needed to increase MVPA and reduce ST in children and adolescents with chronic disease

Conception of a Temperature Sensor Based on 100-μm CoFeSiB Ferromagnetic Wire

In this article, we present the conception of a temperature sensor based on a ferromagnetic microwire having a diameter of about 100~mu ext{m} and a composition of CoFeSiB as 80% Co-Fe and 20% Si-B. We experimentally analyze the influence of the temperature and excitation frequencies on the hysteresis loop of the material. Discussion about how the temperature can act as a measurand through the analysis of the output of the sensor is carried out. Temperature is correlated with the magnetic characteristic of the material, and the results are addressed in light of the recent literature and of the Ising model. All measurements were performed under controlled conditions. An ad hoc setup was developed, and an experimental analysis was carried out to characterize the microwire temperature sensor

Exploitation of Temperature Effect in 100 μm Ferromagnetic Wire

In this paper we present a characterization of a ferromagnetic microwire having a diameter of about 100 μm and a composition of CoFeSiB as 80% Co-Fe, 20% Si, B. We experimentally analyze the influence of the temperature and excitation frequencies on the hysteresis loop of the material. In particular, results and discussion about how the temperature can affect the magnetic characteristic of the material are provided. All measurements have been performed under controlled conditions. A suitable setup has been conceived, realized and an experimental campaign with the characterization of the microwire has been accomplished obtaining very promising results

Investigation of a 100 μm Magnetic Wire for Temperature Sensing based on a Time Domain Readout

In this paper we present an analysis of temperature response of a 100 μm hysteretic wire exploiting a time domain readout. The ferromagnetic wire is composed of 80% Co-Fe, 20% Si, B. The study here conducted investigates the effect of temperature in the microwire with an output measured as time response, which represents an intriguing method to convert the target quantity. The experiments have been accomplished by using a MuMetal® electromagnetic shield with controlled temperature and an acquisition system to process the output. Results here reported evince the suitability of the proposed method which arouses interest for several interesting applications

Improved energy harvesting from wideband vibrations by nonlinear piezoelectric converters

Vibration harvesters typically are linear mass-spring devices working at resonance. A different approach is here proposed based on nonlinear converters that exploit stochastic resonance with white-noise excitation. It consists of a piezoelectric beam converter coupled to permanent magnets to create a bistable system. Under proper conditions, the system bounces between two stable states in response to random excitation, which significantly improves energy harvesting from wide-spectrum vibrations. The background theory is discussed based on a simplified monodimensional model which includes nonlinearity. A cantilever beam with added nonlinearity was simulated by using a MATLAB® Stochastic Differential Equation (SDE) Toolbox demonstrating the expected improvement under white-noise vibrations. Nonlinear converters were then realized by screen printing low-curing-temperature lead zirconate titanate (PZT) films on steel cantilevers equipped with magnets. Experimental tests were performed by measuring both the beam deflection and the output voltage under excitation by random vibrations at varying degree of nonlinearity added to the system. The obtained results show that the performances of the converter in terms of output voltage at parity of mechanical excitation are markedly improved when the system is made bistable. Furthermore, the principle was also preliminarily validated on aMEMSU-shaped cantilever beam that was purposely designed and fabricated in SOI technology. This demonstrates the possibility to downscale the principle here proposed in the perspective of a MEMS harvester based on nonlinear piezoelectric converters