1,403 research outputs found
Measuring the quantum efficiency of single radiating dipoles using a scanning mirror
Using scanning probe techniques, we show the controlled manipulation of the
radiation from single dipoles. In one experiment we study the modification of
the fluorescence lifetime of a single molecular dipole in front of a movable
silver mirror. A second experiment demonstrates the changing plasmon spectrum
of a gold nanoparticle in front of a dielectric mirror. Comparison of our data
with theoretical models allows determination of the quantum efficiency of each
radiating dipole.Comment: 4 pages, 4 figure
The effect of autocorrelation length on the real area of contact and friction behavior of rough surfaces
Autocorrelation length (ACL) is a surface roughness parameter that provides spatial information of surfacetopography that is not included in amplitude parameters such as root-mean-square roughness. This paper presents a relationship between ACL and the friction behavior of a rough surface. The influence of ACL on the peak distribution of a profile is studied based on Whitehouse and Archard’s classical analysis [Whitehouse and ArchardProc. R. Soc. London, Ser. A316, 97 (1970)] and their results are extended to compare profiles from different surfaces. The probability density function of peaks and the mean peak height of a profile are given as functions of its ACL. These results are used to estimate the number of contact points when a rough surface comes into contact with a flat surface, and it is shown that the larger the ACL of the rough surface, the less the number of contact points. Based on Hertzian contact mechanics, it is shown that the real area of contact increases with increasing of number of contact points. Since adhesivefriction force is proportional to the real area of contact, this suggests that the adhesivefriction behavior of a surface will be inversely proportional to its ACL. Results from microscale friction experiments on polished and etchedsiliconsurfaces are presented to verify the analysis
Capturing diagnosis-timing in ICD-coded hospital data: recommendations from the WHO ICD-11 topic advisory group on quality and safety
Purpose To develop a consensus opinion regarding capturing diagnosis-timing in coded hospital data. Methods As part of the World Health Organization International Classification of Diseases-11th Revision initiative, the Quality and Safety Topic Advisory Group is charged with enhancing the capture of quality and patient safety information in morbidity data sets. One such feature is a diagnosis-timing flag. The Group has undertaken a narrative literature review, scanned national experiences focusing on countries currently using timing flags, and held a series of meetings to derive formal recommendations regarding diagnosis-timing reporting. Results The completeness of diagnosis-timing reporting continues to improve with experience and use; studies indicate that it enhances risk-adjustment and may have a substantial impact on hospital performance estimates, especially for conditions/procedures that involve acutely ill patients. However, studies suggest that its reliability varies, is better for surgical than medical patients (kappa in hip fracture patients of 0.7-1.0 versus kappa in pneumonia of 0.2-0.6) and is dependent on coder training and setting. It may allow simpler and more precise specification of quality indicators. Conclusions As the evidence indicates that a diagnosis-timing flag improves the ability of routinely collected, coded hospital data to support outcomes research and the development of quality and safety indicators, the Group recommends that a classification of ‘arising after admission' (yes/no), with permitted designations of ‘unknown or clinically undetermined', will facilitate coding while providing flexibility when there is uncertainty. Clear coding standards and guidelines with ongoing coder education will be necessary to ensure reliability of the diagnosis-timing fla
International variation in the definition of ‘main condition' in ICD-coded health data
Hospital-based medical records are abstracted to create International Classification of Disease (ICD) coded discharge health data in many countries. The ‘main condition' is not defined in a consistent manner internationally. Some countries employ a ‘reason for admission' rule as the basis for the main condition, while other countries employ a ‘resource use' rule. A few countries have recently transitioned from one of these approaches to the other. The definition of ‘main condition' in such ICD data matters when it is used to define a disease cohort to assign diagnosis-related groups and to perform risk adjustment. We propose a method of harmonizing the international definition to enable researchers and international organizations using ICD-coded health data to aggregate or compare hospital care and outcomes across countries in a consistent manner. Inter-observer reliability of alternative harmonization approaches should be evaluated before finalizing the definition and adopting it worldwid
Outer-Sphere Contributions to the Electronic Structure of Type Zero Copper Proteins
Bioinorganic canon states that active-site
thiolate coordination promotes rapid electron transfer (ET)
to and from type 1 copper proteins. In recent work, we have
found that copper ET sites in proteins also can be constructed
without thiolate ligation (called “type zero” sites). Here we
report multifrequency electron paramagnetic resonance
(EPR), magnetic circular dichroism (MCD), and nuclear
magnetic resonance (NMR) spectroscopic data together with
density functional theory (DFT) and spectroscopy-oriented
configuration interaction (SORCI) calculations for type zero Pseudomonas aeruginosa azurin variants. Wild-type (type 1) and type
zero copper centers experience virtually identical ligand fields. Moreover, O-donor covalency is enhanced in type zero centers
relative that in the C112D (type 2) protein. At the same time, N-donor covalency is reduced in a similar fashion to type 1
centers. QM/MM and SORCI calculations show that the electronic structures of type zero and type 2 are intimately linked to the
orientation and coordination mode of the carboxylate ligand, which in turn is influenced by outer-sphere hydrogen bonding
Acute Appendicitis from Metastatic Small Cell Lung Cancer
[West J Emerg Med. 2012;13(1):94–95.
On the generalized Hartley-Hilbert and Fourier-Hilbert transforms
In this paper, we discuss Hartley-Hilbert and Fourier-Hilbert transforms on a certain class of generalized functions. The extended transforms considered in this article are shown to be well-defined, one-to-one, linear and continuous mappings with respect to δ and Δ convergence. Certain theorems are also established
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