255 research outputs found
Microelectromechanical resonators based on an all polymer/carbon nanotube composite structural material
Carboxylated multi-wall carbon-nanotubes (CNTs) monolayers are integrated on microfabricated all-polymer micro-electromechanical systems (pMEMS) resonator bridges on glass substrates. The structural layer of the MEMS bridges is a multilayer blended conductive polymer based on
poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) to which functionalized CNT monolayers are electrostatically attached. The resonance frequency (fres) of electrostatically
actuated pMEMS bridges was measured as a function of their length (32â67 lm) for different multilayer compositions. A significant increase in fres and quality factor (Q) with the addition of CNT monolayers to the PEDOT:PSS structural material is observed, demonstrating that CNT
monolayers can be used to modulate pMEMS resonator properties.Peer ReviewedPostprint (published version
UV laser-induced high resolution cleaving of Si wafers for micro-nano devices and polymeric waveguide characterization
In this work we propose a method for cleaving silicon-based photonic chips by using a laser based micromachining system, consisting of a ND:YVO4laser emitting at 355 nm in nanosecond pulse regime and a micropositioning system. The laser makes grooved marks placed at the desired locations and directions where cleaves have to be initiated, and after several processing steps, a crack appears and propagate along the crystallographic planes of the silicon wafer. This allows cleavage of the chips automatically and with high positioning accuracy, and provides polished vertical facets with better quality than the obtained with other cleaving process, which eases the optical characterization of photonic devices.
This method has been found to be particularly useful when cleaving small-sized chips, where manual cleaving is hard to perform; and also for polymeric waveguides, whose facets get damaged or even destroyed with polishing or manual cleaving processing. Influence of length of the grooved line and speed of processing is studied for a variety of silicon chips. An application for cleaving and characterizing solâgel waveguides is presented. The total amount of light coupled is higher than when using any other procedure
Relationship of promising methods in the detection of anthracycline-induced cardiotoxicity in breast cancer patients
Purpose\ud
It remains challenging to identify patients at risk of anthracycline-induced cardiotoxicity. To better understand the different risk-stratifying approaches, we evaluated 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy and its interrelationship with conventional echocardiography, 2D strain imaging and several biomarkers.\ud
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Methods\ud
We performed 123I-mIBG scintigraphy, conventional and strain echocardiography and biomarker (NT-proBNP, TNF-α, galectin-3, IL-6, troponin I, ST-2 and sFlt-1) assessment in 59 breast cancer survivors 1 year after anthracycline treatment. Interobserver and intermethod variability was calculated on planar and SPECT 123I-mIBG scintigraphy, using the heart/mediastinum (H/M) ratio and washout (WO). Pearsonâs r and multivariate analyses were performed to identify correlations and independent predictors of 123I-mIBG scintigraphy results.\ud
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Results\ud
Delayed planar anterior whole-heart ROI (WH) H/M ratios and WO were the most robust 123I-mIBG parameters. Significant correlations were observed between 123I-mIBG parameters and several conventional echo parameters, global longitudinal and radial strain (GLS and GRS) and galectin-3. The highest Pearsonâs r was observed between delayed H/M ratio and GRS (Pearsonâs r 0.36, p = 0.01). Multivariate analysis showed that GRS was the only independent predictor of the delayed WH H/M ratio (p = 0.023).\ud
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Conclusion\ud
The delayed planar H/M ratio is the most robust 123I-mIBG parameter. It correlates with several conventional echocardiographic parameters, GLS, GRS and galectin-3. Of these, only GRS predicts the H/M ratio
Mechanically tuneable microoptical structure based on PDMS
A system of two solid microlenses with uncoupled optical properties is presented. This structure has been designed in order to have one lens as a reference, while the other one can be mechanically tuneable. The reference lens presents a diameter of 2 mu m and it is placed in the optical axis of the mechanically tuneable lens, which has a diameter of 10 mu m. The proposed microoptical structure has been fabricated in poly(dimethilsiloxane) (PDMS) merging deep reactive ion etching, SU-8 and soft lithography, with a low-cost (mass-production), simple and highly repetitive technology. This device was numerically simulated prior to its fabrication, to optimize its design and improve its behaviour. In addition, an optical characterization of the fabricated devices was carried out. Both simulation and experimental results shows a good agreement, under mechanical actuation behaviour of the reference lens is invariable, while the tuneable lens become an elliptic lens and the interval of Sturm can be observed. These results provide a proof of concept of the proposed devices and validate both the design and the fabrication technology. (C) 2010 Elsevier B.V. All rights reserved
Stress and aging minimization in photoplastic AFM probes
Photostructurable epoxy based resists, like SU-8, are soft materials with a Young's Modulus around 4 GPa, which makes them particularly suitable as base material to fabricate Atomic Force Microscopy (AFM) probes for non-destructive analysis of fragile samples such as biological materials. In this work, it is shown how by introducing an appropriate processing step consisting of a hard bake, the built-in stress gradient of the final structure was considerably reduced. This improved probes properties such as initial bending and aging and proved the epoxy based resists as good candidates for the low-cost fabrication of micromechanical systems (MEMS) and devices in general. (C) 2008 Elsevier B.V. All rights reserved
Nanoscale imaging of buried topological defects with quantitative X-ray magnetic microscopy
This work is licensed under a Creative Commons Attribution 4.0
International License.-- et al.Advances in nanoscale magnetism increasingly require characterization tools providing detailed descriptions of magnetic configurations. Magnetic transmission X-ray microscopy produces element specific magnetic domain images with nanometric lateral resolution in films up to âŒ100 nm thick. Here we present an imaging method using the angular dependence of magnetic contrast in a series of high resolution transmission X-ray microscopy images to obtain quantitative descriptions of the magnetization (canting angles relative to surface normal and sense). This method is applied to 55-120 nm thick ferromagnetic NdCo 5 layers (canting angles between 65° and 22°), and to a NdCo 5 film covered with permalloy. Interestingly, permalloy induces a 43° rotation of Co magnetization towards surface normal. Our method allows identifying complex topological defects (merons or 1/2 skyrmions) in a NdCo 5 film that are only partially replicated by the permalloy overlayer. These results open possibilities for the characterization of deeply buried magnetic topological defects, nanostructures and devices.Work supported by Spanish MINECO under grant FIS2013-45469. A. Hierro-Rodriguez acknowledges support from FCT of Portugal (Grant SFRH/BPD/90471/2012). C. Blanco-RoldĂĄn thanks support from CSIC JAE Predoc Program.Peer Reviewe
On handling urban informality in southern Africa
In this article I reconsider the handling of urban informality by urban planning and management systems in southern Africa. I argue that authorities have a fetish about formality and that this is fuelled by an obsession with urban modernity. I stress that the desired city, largely inspired by Western notions of modernity, has not been and cannot be realized. Using illustrative cases of topâdown interventions, I highlight and interrogate three strategies that authorities have deployed to handle informality in an effort to create or defend the modern city. I suggest that the fetish is built upon a desire for an urban modernity based on a concept of formal order that the authorities believe cannot coexist with the âdisorderâ and spatial âunrulinessâ of informality. I question the authorities' conviction that informality is an abomination that needs to be âconvertedâ, dislocated or annihilated. I conclude that the very configuration of urban governance and socio-economic systems in the region, like the rest of sub-Saharan Africa, renders informality inevitable and its eradication impossible
Implementation of the eira 3 intervention by targeting primary health care practitioners: Effectiveness in increasing physical activity
The World Health Organization (WHO) estimated that physical inactivity (PI) is responsible for 20 to 30% of all non-communicable diseases. We aimed to analyze the effectiveness of a multiple health behavior change (MHBC) intervention to increase physical activity (PA) in patients 45 to 75 years old who had at least 2 of 3 unhealthy behaviors (tobacco use, reduced fruit and vegetable consumption, and insufficient PA). The MHBC intervention is based on the Transtheoretical Model and the conceptual framework of the â5 Aâsâ and includes an individually tailored intervention, group sessions, and the use of community resources. We included 3062 participants, 1481 in the intervention group and 1581 in the control group. After 12 months, there were no differences in PA intensity measured by metabolic_equivalent_of_task_minutes/week (adjusted mean difference: 284.093, 95% CI: -298.24, 866.42) nor in the proportion of participants who increased PA levels to moderate or high (OR: 1.02, 95% CI: 0.85, 1.23; p = 0.822), and no differences in blood pressure, weight loss, or waist circumference. We found an increased proportion of patients in the intervention group who followed the WHO recommendations for PA (OR: 1.29; 95% CI: 1.04, 1.60; p = 0.02). We concluded that the intervention did not lead to a significant increase in PA. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Role of personal aptitudes as determinants of incident morbidity, lifestyles, quality of life, use of health services, and mortality (DESVELA cohort): quantitative study protocol for a prospective cohort study in a hybrid analysis
IntroductionThe healthcare and well-being of the population depend on multiple factors and should adapt to societal changes. The opposite is also occurring; society has evolved concerning the individualsâ approach to their care, which includes participation in decision-making processes. In this scenario, health promotion and prevention become crucial to provide an integrated perspective in the organization and management of the health systems.Health status and well-being depend on many aspects, determinants of health, which in turn may be modulated by individual behavior. Certain models and frameworks try to study the determinants of health and individual human behaviors, separately. However, the interrelation between these two aspects has not been examined in our population.Our main objective is to analyze whether personal aptitudes related to behaviors are independently associated with the incidence of morbidity. A secondary objective will enquire whether these personal aptitudes are independently associated with lower all-cause mortality, enhanced adoption of healthy lifestyles, higher quality of life, and lower utilization of health services during follow-up.MethodsThis protocol addresses the quantitative branch of a multicenter project (10 teams) for the creation of a cohort of at least 3,083 persons aged 35 to 74 years from 9 Autonomous Communities (AACC). The personal variables to evaluate are self-efficacy, activation, health literacy, resilience, locus of control, and personality traits. Socio-demographic covariates and social capital will be recorded. A physical examination, blood analysis, and cognitive evaluation will be carried out.Several sets of six Cox models (one for each independent variable) will analyze the incidence of morbidity (objective 1); all-cause mortality and the rest of the dependent variables (objective 2). The models will be adjusted for the indicated covariates, and random effects will estimate Potential heterogeneity between AACC.DiscussionThe analysis of the association of certain behavioral patterns and determinants of health is essential and will contribute to improving health promotion and prevention strategies. The description of the individual elements and interrelated aspects that modulate the onset and persistence of diseases will allow the evaluation of their role as prognostic factors and contribute to the development of patient-tailored preventive measures and healthcare.Clinical Trial Registration: ClinicalTrials.gov, NCT04386135. Registered on April 30, 2020
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