67 research outputs found
Magnetic metamaterial superlens for increased range wireless power transfer.
The ability to wirelessly power electrical devices is becoming of greater urgency as a component of energy conservation and sustainability efforts. Due to health and safety concerns, most wireless power transfer (WPT) schemes utilize very low frequency, quasi-static, magnetic fields; power transfer occurs via magneto-inductive (MI) coupling between conducting loops serving as transmitter and receiver. At the "long range" regime - referring to distances larger than the diameter of the largest loop - WPT efficiency in free space falls off as (1/d)(6); power loss quickly approaches 100% and limits practical implementations of WPT to relatively tight distances between power source and device. A "superlens", however, can concentrate the magnetic near fields of a source. Here, we demonstrate the impact of a magnetic metamaterial (MM) superlens on long-range near-field WPT, quantitatively confirming in simulation and measurement at 13-16 MHz the conditions under which the superlens can enhance power transfer efficiency compared to the lens-less free-space system
Electronically reconfigurable metal-on-silicon metamaterial
Reconfigurable metamaterial-based apertures can play a unique role in both
imaging and in beam-forming applications, where current technology relies
mostly on the fabrication and integration of large detector or antenna arrays.
Here, we report the experimental demonstration of a voltage-controlled,
silicon-based electromagnetic metamaterial operating in the W-band (75-110
GHz). In this composite semiconductor metamaterial, patterned gold metamaterial
elements serve both to manage electromagnetic wave propagation while
simultaneously acting as electrical Schottky contacts that control the local
conductivity of the semiconductor substrate. The active device layers consist
of a patterned metal on a 2-{\mu}m-thick n-doped silicon layer, adhesively
bonded to a transparent Pyrex wafer. The transmittance of the composite
metamaterial can be modulated over a given frequency band as a function of bias
voltage. We demonstrate a quantitative understanding of the composite device
through the application of numerical approaches that simultaneously treat the
semiconductor junction physics as well as wave propagation.Comment: 28 double-spaced pages, 8 figure
The nursing work environment and quality of care: Content analysis of comments made by registered nurses responding to the Essentials of Magnetism II scale
Aim:
To report a qualitative study of themes Registered Nurses raised spontaneously about their work environment, in a cross‐sectional survey study when responding to the Essentials of Magnetism II (EOMII) scale.
Design:
Qualitative descriptive survey.
Methods:
At the end of the EOMII scale, a free form text section was included asking nurses to add comments about their ward/work environment. Of the 247 nurses who completed the EOMII scale, 30% (N = 75) provided comments. Inductive content analysis was used to analyse the textual information generated.
Results:
Three key themes emerged: “nurses need nurses to nurse”; working as a team and workplace environment. Participants described issues they were facing which comprised high turnover rates, inadequate staffing levels, increasing workload and high stress levels. Particular attention was drawn to the role of the ward manager in promoting a positive work environment, good teamwork and quality patient care
Monitoring the newly qualified nurses in Sweden: the Longitudinal Analysis of Nursing Education (LANE) study
BACKGROUND: The Longitudinal Analysis of Nursing Education (LANE) study was initiated in 2002, with the aim of longitudinally examining a wide variety of individual and work-related variables related to psychological and physical health, as well as rates of employee and occupational turnover, and professional development among nursing students in the process of becoming registered nurses and entering working life. The aim of this paper is to present the LANE study, to estimate representativeness and analyse response rates over time, and also to describe common career pathways and life transitions during the first years of working life. METHODS: Three Swedish national cohorts of nursing students on university degree programmes were recruited to constitute the cohorts. Of 6138 students who were eligible for participation, a total of 4316 consented to participate and responded at baseline (response rate 70%). The cohorts will be followed prospectively for at least three years of their working life. RESULTS: Sociodemographic data in the cohorts were found to be close to population data, as point estimates only differed by 0-3% from population values. Response rates were found to decline somewhat across time, and this decrease was present in all analysed subgroups. During the first year after graduation, nearly all participants had qualified as nurses and had later also held nursing positions. The most common reason for not working was due to maternity leave. About 10% of the cohorts who graduated in 2002 and 2004 intended to leave the profession one year after graduating, and among those who graduated in 2006 the figure was almost twice as high. Intention to leave the profession was more common among young nurses. In the cohort who graduated in 2002, nearly every fifth registered nurse continued to further higher educational training within the health professions. Moreover, in this cohort, about 2% of the participants had left the nursing profession five years after graduating. CONCLUSION: Both high response rates and professional retention imply a potential for a thorough analysis of professional practice and occupational health
Recommendations on basic requirements for intensive care units: structural and organizational aspects
OBJECTIVE: To provide guidance and recommendations for the planning or renovation of intensive care units (ICUs) with respect to the specific characteristics relevant to organizational and structural aspects of intensive care medicine.
METHODOLOGY: The Working Group on Quality Improvement (WGQI) of the European Society of Intensive Care Medicine (ESICM) identified the basic requirements for ICUs by a comprehensive literature search and an iterative process with several rounds of consensus finding with the participation of 47 intensive care physicians from 23 countries. The starting point of this process was an ESICM recommendation published in 1997 with the need for an updated version.
RESULTS: The document consists of operational guidelines and design recommendations for ICUs. In the first part it covers the definition and objectives of an ICU, functional criteria, activity criteria, and the management of equipment. The second part deals with recommendations with respect to the planning process, floorplan and connections, accommodation, fire safety, central services, and the necessary communication systems.
CONCLUSION: This document provides a detailed framework for the planning or renovation of ICUs based on a multinational consensus within the ESIC
Trends in der Epidemiologie, Therapie und den Behandlungsergebnissen von Kopf-Hals-Tumoren: Eine populationsbezogene Langzeitanalyse der Thüringer Krebsregister von 1996 bis 2011
Trends in der Epidemiologie, Therapie und den Behandlungsergebnissen von Kopf-Hals-Tumoren: Eine populationsbezogene Langzeitanalyse der Thüringer Krebsregister von 1996 bis 2011
Nature
regulates complex structures in space and time via feedback
loops, kinetically controlled transformations, and under energy dissipation
to allow non-equilibrium processes. Although man-made static self-assemblies
realize excellent control over hierarchical structures via molecular
programming, managing their temporal destiny by self-regulation is
a largely unsolved challenge. Herein, we introduce a generic concept
to control the time domain by programming the lifetimes of switchable
self-assemblies in closed systems. We conceive dormant deactivators
that, in combination with fast promoters, enable a unique kinetic
balance to establish an autonomously self-regulating, transient pH-state,
whose duration can be programmed over orders of magnitudefrom
minutes to days. Coupling this non-equilibrium state to pH-switchable
self-assemblies allows predicting their assembly/disassembly fate
in time, similar to a precise self-destruction mechanism. We demonstrate
a platform approach by programming self-assembly lifetimes of block
copolymers, nanoparticles, and peptides, enabling dynamic materials
with a self-regulation functionality
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