Modeling and Dynamic performance of Energy Storage -Rotary Series Elastic Actuator for Lumbar Support Exoskeleton

The assistive exoskeletons are rapidly being developed to collaborate with humans, and the demand for the safety of human-robot interaction has become more crucial. Series elastic actuators (SEAs) have recently been developed in various fields for a variety of possible advantages, such as providing a safe human-robot interaction, reducing the impacts’ effects, and increasing energy efficiency. However, achieving the good dynamic performances of SEAs is still challenging, especially fulfilling the high bandwidth with good compliance. In this rapidly growing research field, the actuation system involving the storage device combined with the rotary series elastic actuator (ES-RSEA) is being investigated to exploit the biomechanical energy while maintaining compliance features. In this article, the modeling and control design of the energy storage rotary series elastic actuator (ES-RSEA) for the lumbar support exoskeleton is proposed, and its dynamic performances are analyzed. The ES-RSEA was designed based on storing the kinetic energy during the lifting tasks and generating assistive torque while maintaining excellent compliant characteristics. The dynamic performances and characteristics of ES-RSEA are presented in terms of force sensitivity, level of compliance, transmission ratio, and bandwidth. Simulation studies indicate that the actuator can provide excellent dynamic performance through its high bandwidth (12.44 Hz) and high force sensitivity. At the same time, it shows excellent compliance and good torque transmissibility in the low-frequency range. A PID controller can achieve high torque tracking performance and good dynamic response with a root-mean-square (RMS) error of 0.1 N.m. This article demonstrates the excellent performance and characteristics of ES-RSEA to guarantee compliance and high response to prevent injury of undesired human movements

P171Elevated free fetal haemoglobin threatens vasculoprotection in the fetal circulation of preeclamptic pregnancy

Placental up-regulation of free fetal haemoglobin (fHbF) occurs in preeclamptic (PE) pregnancy. Heme oxygenase-1 (HO-1) is an important vasculoprotective enzyme in the catabolism of the associated heme porphyrin structure. We have previously shown that fHbF negatively influences the vasculoprotective capacity of the fetal circulation. Here we study fHbF levels in the fetal cord blood of pregnancies complicated by PE; a pathology associated with dysregulated fetoplacental vascular tone. We have previously shown that fHbF binds nitric oxide (NO) to elicit elevated vascular resistance in the fetoplacental circulation, using ex vivo human dual placental perfusion and in vitro placental endothelial cell shear stress studies. Furthermore, fHbF causes morphological changes to the fetoplacental endothelium. Here we hypothesise that elevated levels of fHbF in fetal plasma associated with placental pathology contribute to fetoplacental hypertension. Purpose: To evaluate and derive a robust cord blood collection and processing protocol for the accurate measurement of fetal plasma fHbF levels in normal and PE pregnancies. Methods: Fetal venous cord blood was collected by syringe and needle, or Vacutainer method into either EDTA or citrate tubes, within 10 minutes of partum. Plasma recovery occurred immediately, or after 30 minutes, prior to centrifugation at 2000g x 10 min at room temperature. Following evaluation to reduce mechanical haemolysis, newly collected normal & PE plasma (n=13 & 6, respectively) was subjected to ELISAs for HbF and HO-1. Results: Venipuncture collection of cord venous blood taken from the cord-placenta insertion point by Vacutainer system with a 21G needle, into citrate collection tubes with immediate centrifugation prevented mechanical haemolysis. There was no difference in plasma HO-1 between groups (medians = 5.9 & 5.3 ng/mL; normal & PE, respectively; Mann-Whitney). Whilst there was no difference in fHbF between groups (Mann-Whitney), variability was high in the PE group and there were some very high values for fHbF compared to the normal range, whilst fHbF values in the control group were within a tighter lower range (medians & ranges = 45.9 & 0-206 and 118.8 & 29-640 μg/mL). Conclusion: Fetal plasma HO-1 levels appear stable in preeclamptic fetal plasma, permitting fHbF to remain unchecked in some cases. High pathophysiological levels of fHbF in some cases of PE pregnancies are capable of evoking elevated vascular resistance within the fetoplacental circulation, caused by nitric oxide sequestration and disruption to the endothelium. Further evaluation is require

The application of useless Japanese inventions for requirements elicitation in information security

Rules of requirements elicitation in security are broken through the use of Chindōgu, by designing impractical security countermeasures in the first instance, then using these to create usable security requirements. We present a process to conceive the requirements in Chindōgu form. We evaluate the usefulness of this process by applying it in three workshops with data gathered from a European rail company, and comparing requirements elicited by this process with a set of control requirements

Cross-Reactive Antibodies to Pandemic (H1N1) 2009 Virus, Singapore

10.3201/eid1605.091678Emerging Infectious Diseases165874-87

Low-complexity BCH codes with optimized interleavers for DQPSK systems with laser phase noise

The presence of high phase noise in addition to additive white Gaussian noise in coherent optical systems affects the performance of forward error correction (FEC) schemes. In this paper, we propose a simple scheme for such systems, using block interleavers and binary Bose–Chaudhuri–Hocquenghem (BCH) codes. The block interleavers are specifically optimized for differential quadrature phase shift keying modulation. We propose a method for selecting BCH codes that, together with the interleavers, achieve a target post-FEC bit error rate (BER). This combination of interleavers and BCH codes has very low implementation complexity. In addition, our approach is straightforward, requiring only short pre-FEC simulations to parameterize a model, based on which we select codes analytically. We aim to correct a pre-FEC BER of around (Formula presented.). We evaluate the accuracy of our approach using numerical simulations. For a target post-FEC BER of (Formula presented.), codes selected using our method result in BERs around 3(Formula presented.) target and achieve the target with around 0.2 dB extra signal-to-noise ratio

The combined diabetes and renal control trial (C-DIRECT) - a feasibility randomised controlled trial to evaluate outcomes in multi-morbid patients with diabetes and on dialysis using a mixed methods approach

Background: This cluster randomised controlled trial set out to investigate the feasibility and acceptability of the “Combined Diabetes and Renal Control Trial” (C-DIRECT) intervention, a nurse-led intervention based on motivational interviewing and self-management in patients with coexisting end stage renal diseases and diabetes mellitus (DM ESRD). Its efficacy to improve glycaemic control, as well as psychosocial and self-care outcomes were also evaluated as secondary outcomes. Methods: An assessor-blinded, clustered randomised-controlled trial was conducted with 44 haemodialysis patients with DM ESRD and ≥ 8% glycated haemoglobin (HbA1c), in dialysis centres across Singapore. Patients were randomised according to dialysis shifts. 20 patients were assigned to intervention and 24 were in usual care. The C-DIRECT intervention consisted of three weekly chair-side sessions delivered by diabetes specialist nurses. Data on recruitment, randomisation, and retention, and secondary outcomes such as clinical endpoints, emotional distress, adherence, and self-management skills measures were obtained at baseline and at 12 weeks follow-up. A qualitative evaluation using interviews was conducted at the end of the trial. Results: Of the 44 recruited at baseline, 42 patients were evaluated at follow-up. One patient died, and one discontinued the study due to deteriorating health. Recruitment, retention, and acceptability rates of C-DIRECT were generally satisfactory HbA1c levels decreased in both groups, but C-DIRECT had more participants with HbA1c < 8% at follow up compared to usual care. Significant improvements in role limitations due to physical health were noted for C-DIRECT whereas levels remained stable in usual care. No statistically significant differences between groups were observed for other clinical markers and other patient-reported outcomes. There were no adverse effects. Conclusions: The trial demonstrated satisfactory feasibility. A brief intervention delivered on bedside as part of routine dialysis care showed some benefits in glycaemic control and on QOL domain compared with usual care, although no effect was observed in other secondary outcomes. Further research is needed to design and assess interventions to promote diabetes self-management in socially vulnerable patients

Direct observation of room-temperature out-of-plane ferroelectricity and tunneling electroresistance at the two-dimensional limit

Out-of-plane ferroelectricity with a high transition temperature in nanometer-scale films is required to miniaturize electronic devices. Direct visualization of stable ferroelectric polarization and its switching behavior in atomically thick films is critical for achieving this goal. Here, ferroelectric order at room temperature in the two-dimensional limit is demonstrated in tetragonal BiFeO3 ultrathin films. Using aberration-corrected scanning transmission electron microscopy, we directly observed robust out-of-plane spontaneous polarization in one-unitcell-thick BiFeO3 films. High-resolution piezoresponse force microscopy measurements show that the polarization is stable and switchable, whereas a tunneling electroresistance effect of up to 370% is achieved in BiFeO3 films. Based on first-principles calculations and Kelvin probe force microscopy measurements, we explain the mechanism of polarization stabilization by the ionic displacements in oxide electrode and the surface charges. Our results indicate that critical thickness for ferroelectricity in the BiFeO3 film is virtually absent, making it a promising candidate for high-density nonvolatile memories

Direct observation of room-temperature out-of-plane ferroelectricity and tunneling electroresistance at the two-dimensional limit

Out-of-plane ferroelectricity with a high transition temperature in nanometer-scale films is required to miniaturize electronic devices. Direct visualization of stable ferroelectric polarization and its switching behavior in atomically thick films is critical for achieving this goal. Here, ferroelectric order at room temperature in the two-dimensional limit is demonstrated in tetragonal BiFeO3 ultrathin films. Using aberration-corrected scanning transmission electron microscopy, we directly observed robust out-of-plane spontaneous polarization in one-unitcell-thick BiFeO3 films. High-resolution piezoresponse force microscopy measurements show that the polarization is stable and switchable, whereas a tunneling electroresistance effect of up to 370% is achieved in BiFeO3 films. Based on first-principles calculations and Kelvin probe force microscopy measurements, we explain the mechanism of polarization stabilization by the ionic displacements in oxide electrode and the surface charges. Our results indicate that critical thickness for ferroelectricity in the BiFeO3 film is virtually absent, making it a promising candidate for high-density nonvolatile memories

Private Sector Participation and Health System Performance in Sub-Saharan Africa

BACKGROUND: The role of the private health sector in developing countries remains a much-debated and contentious issue. Critics argue that the high prices charged in the private sector limits the use of health care among the poorest, consequently reducing access and equity in the use of health care. Supporters argue that increased private sector participation might improve access and equity by bringing in much needed resources for health care and by allowing governments to increase focus on underserved populations. However, little empirical exists for or against either side of this debate. METHODOLOGY/PRINCIPAL FINDINGS: We examine the association between private sector participation and self-reported measures of utilization and equity in deliveries and treatment of childhood respiratory disease using regression analysis, across a sample of nationally-representative Demographic and Health Surveys from 34 SSA economies. We also examine the correlation between private sector participation and key background factors (socioeconomic development, business environment and governance) and use multivariate regression to control for potential confounders. Private sector participation is positively associated with greater overall access and reduced disparities between rich and poor as well as urban and rural populations. The positive association between private sector participation and improved health system performance is robust to controlling for confounders including per capita income and maternal education. Private sector participation is positively correlated with measures of socio-economic development and favorable business environment. CONCLUSIONS/SIGNIFICANCE: Greater participation is associated with favorable intermediate outcomes in terms of access and equity. While these results do not establish a causal link between private sector participation and health system performance, they suggest that there is no deleterious link between private sector participation and health system performance in SSA