RF-MEMS switch actuation pulse optimization using Taguchi's method

Copyright @ 2011 Springer-VerlagReliability and longevity comprise two of the most important concerns when designing micro-electro-mechanical-systems (MEMS) switches. Forcing the switch to perform close to its operating limits underlies a trade-off between response bandwidth and fatigue life due to the impact force of the cantilever touching its corresponding contact point. This paper presents for first time an actuation pulse optimization technique based on Taguchi’s optimization method to optimize the shape of the actuation pulse of an ohmic RF-MEMS switch in order to achieve better control and switching conditions. Simulation results show significant reduction in impact velocity (which results in less than 5 times impact force than nominal step pulse conditions) and settling time maintaining good switching speed for the pull down phase and almost elimination of the high bouncing phenomena during the release phase of the switch

A finer grained approach to psychological capital and work performance

Purpose Psychological capital is a set of personal resources comprised by hope, efficacy, optimism, and resilience, which previous research has supported as being valuable for general work performance. However, in today’s organizations, a multidimensional approach is required to understanding work performance, thus, we aimed to determine whether psychological capital improves proficiency, adaptivity, and proactivity, and also whether hope, efficiency, resilience, and optimism have a differential contribution to the same outcomes. Analyzing the temporal meaning of each psychological capital dimension, this paper theorizes the relative weights of psychological capital dimensions on proficiency, adaptivity, and proactivity, proposing also that higher relative weight dimensions are helpful to cope with job demands and perform well. Methodology Two survey studies, the first based on cross-sectional data and the second on two waves of data, were conducted with employees from diverse organizations, who provided measures of their psychological capital, work performance, and job demands. Data was modeled with regression analysis together with relative weights analysis. Findings Relative weights for dimensions of psychological capital were supported as having remarkable unique contributions for proficient, adaptive, and proactive behavior, particularly when job demands were high. Originality/Value We concluded that organizations facing high job demands should implement actions to enhance psychological capital dimensions; however, those actions should focus on the specific criterion of performance of interest

A study to explore if dentists’ anxiety affects their clinical decision-making

Aims To develop a measure of dentists’ anxiety in clinical situations; to establish if dentists’ anxiety in clinical situations affected their self-reported clinical decision-making; to establish if occupational stress, as demonstrated by burnout, is associated with anxiety in clinical situations and clinical decision-making; and to explore the relationship between decision-making style and the clinical decisions which are influenced by anxiety. Design Cross-sectional study. Setting Primary Dental Care. Subjects and methods A questionnaire battery [Maslach Burnout Inventory, measuring burnout; Melbourne Decision Making Questionnaire, measuring decision-making style; Dealing with Uncertainty Questionnaire (DUQ), measuring coping with diagnostic uncertainty; and a newly designed Dentists’ Anxieties in Clinical Situations Scale, measuring dentists’ anxiety (DACSS-R) and change of treatment (DACSS-C)] was distributed to dentists practicing in Nottinghamshire and Lincolnshire. Demographic data were collected and dentists gave examples of anxiety-provoking situations and their responses to them. Main outcome measure Respondents’ self-reported anxiety in various clinical situations on a 11-point Likert Scale (DACSS-R) and self-reported changes in clinical procedures (Yes/No; DACSS-C). The DACSS was validated using multiple t-tests and a principal component analysis. Differences in DACSS-R ratings and burnout, decision-making and dealing with uncertainty were explored using Pearson correlations and multiple regression analysis. Qualitative data was subject to a thematic analysis. Results The DACSS-R revealed a four-factor structure and had high internal reliability (Cronbach’s α = 0.94). Those with higher DACSS-R scores of anxiety were more likely to report changes in clinical procedures (DACSS-C scores). DACSS-R scores were associated with decision-making self-esteem and style as measured by the MDMQ and all burnout subscales, though not with scores on the DUQ scale. Conclusion Dentists’ anxiety in clinical situations does affect the way that dentists work clinically, as assessed using the newly designed and validated DACSS. This anxiety is associated with measures of burnout and decision-making style with implications for training packages for dentists

The evaluation of a continuing professional development package for primary care dentists designed to reduce stress, build resilience and improve clinical decision-making

Introduction: Stress and burnout are widely accepted as a problem for primary care dental practitioners. Previous programmes to address this issue have met with some success. Burnout is associated with poor coping skills and emotion regulation, and increased rates of clinical errors. Anxiety is associated with poor decision-making and is thought to be associated with poor clinical decision-making. Attempts to improve decision-making use increasing meta-awareness and review of thinking processes. Bibliotherapy is an effective method of delivering cognitive behavioural therapy as self-help or guided self-help (with some therapist input) formats. Objective: To evaluate the efficacy of a specially designed CPD package which was designed to improve coping skills, build resilience and reduce the impact of anxiety on dentists’ clinical decision-making. Design: A multi-centred quasi-experiment Setting: Lincolnshire and Nottinghamshire (England) 2014 Materials and methods: Thirty-five volunteer primary care dentists used two versions (self-help [SH] and guided self-help [GSH], which included a 3 hour workshop) of a specially written cognitive-behavioural-therapy bibliotherapy programme designed to improve well-being and decision-making. Main Outcome Measures: The main outcome measures were dentists’ burnout, depression, anxiety, stress and decision-making style. Data were also collected on use and evaluation of the programme. Results: At 6 weeks there was a clinically and statistically significant reduction in depression, anxiety and stress levels, a statistically significant reduction in burnout (emotional exhaustion) and hypervigilant decision-making and an increase in personal achievement (burnout). The improvements in depression, stress, emotional exhaustion and hypervigilant decision-making were maintained at 6 months. Dentists were overwhelmingly positive in their evaluation of the project and used most of its contents. Conclusion: With the caveat of small numbers and the lack of a no-treatment control, this project demonstrated that a self-help package can be highly acceptable to dentists and, in the short-to-medium term, improve dentists’ well-being and decision-making with implications for patient safety

Morphing in nature and beyond: a review of natural and synthetic shape-changing materials and mechanisms

Shape-changing materials open an entirely new solution space for a wide range of disciplines: from architecture that responds to the environment and medical devices that unpack inside the body, to passive sensors and novel robotic actuators. While synthetic shape-changing materials are still in their infancy, studies of biological morphing materials have revealed key paradigms and features which underlie efficient natural shape-change. Here, we review some of these insights and how they have been, or may be, translated to artificial solutions. We focus on soft matter due to its prevalence in nature, compatibility with users and potential for novel design. Initially, we review examples of natural shape-changing materials—skeletal muscle, tendons and plant tissues—and compare with synthetic examples with similar methods of operation. Stimuli to motion are outlined in general principle, with examples of their use and potential in manufactured systems. Anisotropy is identified as a crucial element in directing shape-change to fulfil designed tasks, and some manufacturing routes to its achievement are highlighted. We conclude with potential directions for future work, including the simultaneous development of materials and manufacturing techniques and the hierarchical combination of effects at multiple length scales.</p

Microvascular complications of type 2 diabetes mellitus

Background: Type 2 diabetes mellitus (T2DM) is a chronic, non communicable, multi-system disease that has reached epidemic proportions. Chronic exposure to hyperglycaemia affects the microvasculature, eventually leading to diabetic nephropathy, retinopathy and neuropathy with high impact on the quality of life and overall life expectancy. Sexual dysfunction is an often-overlooked microvascular complication of T2DM, with a complex pathogenesis originating from endothelial dysfunction. Objective: The purpose of this review is to present current definitions, epidemiological data and risk factors for diabetic retinopathy, nephropathy, neuropathy and sexual dysfunction. We also describe the clinical and laboratory evaluation that is mandatory for the diagnosis of these conditions. Methods: A comprehensive review of the literature was performed to identify data from clinical studies for the prevalence, risk factors and diagnostic methods of microvascular complications of T2DM. Results: Diabetic nephropathy and retinopathy affect approximately 25% of patients with T2DM; diabetic neuropathy is encountered in almost 50% of the diabetic population, while the prevalence of erectile dysfunction ranges from 35-90% in diabetic men. The duration of T2DM along with glycemic, blood pressure and lipid control are common risk factors for the development of these complications. Criteria for the diagnosis of these conditions are well established, but exclusion of other causes is mandatory. Conclusion: Early detection of microvascular complications associated with T2DM is important, as early intervention leads to better outcomes. However, this requires awareness of their definition, prevalence and diagnostic modalities. © 2020 Bentham Science Publishers