1,252 research outputs found
Platinum(II), palladium(II), nickel(II), and gold(I) complexes of the “electrospray-friendly” thiolate ligands 4-SC₅H₄N- and 4-SC₆H₄OMe-
The series of platinum(II), palladium(II), and nickel(II) complexes [ML₂(dppe)] [M = Ni, Pd, Pt; L = 4-SC₅H₄N or 4-SC₆H₄OMe; dppe = Ph₂PCH₂CH₂PPh₂] containing pyridine-4-thiolate or 4-methoxybenzenethiolate ligands, together with the corresponding gold(I) complexes [AuL(PPh3)], were prepared and their electrospray ionization mass spectrometric behavior compared with that of the thiophenolate complexes [M(SPh)₂(dppe)] (M = Ni, Pd, Pt) and [Au(SPh)(PPh₃)]. While the pyridine-4-thiolate complexes yielded protonated ions of the type [M + H]+ and [M + 2H]²+ ions in the Ni, Pd, and Pt complexes, an [M + H]+ ion was only observed for the platinum derivative of 4-methoxybenzenethiolate. Other ions, which dominated the spectra of the thiophenolate complexes, were formed by thiolate loss and aggregate formation. The X-ray crystal structure of [Pt(SC₆H₄OMe-4)₂(dppe)] is also reported
Spin-orbit coupling and phase-coherence in InAs nanowires
We investigated the magnetotransport of InAs nanowires grown by selective
area metal-organic vapor phase epitaxy. In the temperature range between 0.5
and 30 K reproducible fluctuations in the conductance upon variation of the
magnetic field or the back-gate voltage are observed, which are attributed to
electron interference effects in small disordered conductors. From the
correlation field of the magnetoconductance fluctuations the phase-coherence
length l_phi is determined. At the lowest temperatures l_phi is found to be at
least 300 nm, while for temperatures exceeding 2 K a monotonous decrease of
l_phi with temperature is observed. A direct observation of the weak
antilocalization effect indicating the presence of spin-orbit coupling is
masked by the strong magnetoconductance fluctuations. However, by averaging the
magnetoconductance over a range of gate voltages a clear peak in the
magnetoconductance due to the weak antilocalization effect was resolved. By
comparison of the experimental data to simulations based on a recursive
two-dimensional Green's function approach a spin-orbit scattering length of
approximately 70 nm was extracted, indicating the presence of strong spin-orbit
coupling.Comment: 8 pages, 7 figure
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Properties of Multivesicular Release from Mouse Rod Photoreceptors Support Transmission of Single-Photon Responses
Vision under starlight requires rod photoreceptors to transduce and transmit single-photon responses to the visual system. Small single-photon voltage changes must therefore cause detectable reductions in glutamate release. We found that rods achieve this by employing mechanisms that enhance release regularity and its sensitivity to small voltage changes. At the resting membrane potential in darkness, mouse rods exhibit coordinated and regularly timed multivesicular release events, each consisting of ~17 vesicles and occurring two to three times more regularly than predicted by Poisson statistics. Hyperpolarizing rods to mimic the voltage change produced by a single photon abruptly reduced the probability of multivesicular release nearly to zero with a rebound increase at stimulus offset. Simulations of these release dynamics indicate that this regularly timed, multivesicular release promotes transmission of single-photon responses to post-synaptic rod-bipolar cells. Furthermore, the mechanism is efficient, requiring lower overall release rates than uniquantal release governed by Poisson statistics
Development of a Coordinate Measuring Machine-Based Inspection Planning System for Industry 4.0
Industry 4.0 represents a new paradigm which creates new requirements in the area of manufacturing and manufacturing metrology such as to reduce the cost of product, flexibility, mass customization, quality of product, high level of digitalization, optimization, etc., all of which contribute to smart manufacturing and smart metrology systems. This paper presents a developed inspection planning system based on CMM as support of the smart metrology within Industry 4.0 or manufacturing metrology 4.0 (MM4.0). The system is based on the application of three AI techniques such as engineering ontology (EO), GA and ants colony optimization (ACO). The developed system consists of: the ontological knowledge base; the mathematical model for generating strategy of initial MP; the model of analysis and optimization of workpiece setups and probe configuration; the path simulation model in MatLab, PTC Creo and STEP-NC Machine software, and the model of optimization MP by applying ACO. The advantage of the model is its suitability for monitoring of the measurement process and digitalization of the measurement process planning, simulation carried out and measurement verification based on CMM, reduction of the preparatory measurement time as early as in the inspection planning phase and minimizing human involvement or human errors through intelligent planning, which directly influences increased production efficiency, competitiveness, and productivity of enterprises. The measuring experiment was performed using a machined prismatic workpiece (PW)
Development of a Coordinate Measuring Machine-Based Inspection Planning System for Industry 4.0
Industry 4.0 represents a new paradigm which creates new requirements in the area of manufacturing and manufacturing metrology such as to reduce the cost of product, flexibility, mass customization, quality of product, high level of digitalization, optimization, etc., all of which contribute to smart manufacturing and smart metrology systems. This paper presents a developed inspection planning system based on CMM as support of the smart metrology within Industry 4.0 or manufacturing metrology 4.0 (MM4.0). The system is based on the application of three AI techniques such as engineering ontology (EO), GA and ants colony optimization (ACO). The developed system consists of: the ontological knowledge base; the mathematical model for generating strategy of initial MP; the model of analysis and optimization of workpiece setups and probe configuration; the path simulation model in MatLab, PTC Creo and STEP-NC Machine software, and the model of optimization MP by applying ACO. The advantage of the model is its suitability for monitoring of the measurement process and digitalization of the measurement process planning, simulation carried out and measurement verification based on CMM, reduction of the preparatory measurement time as early as in the inspection planning phase and minimizing human involvement or human errors through intelligent planning, which directly influences increased production efficiency, competitiveness, and productivity of enterprises. The measuring experiment was performed using a machined prismatic workpiece (PW)
Diagnosis and outcome of oesophageal Crohn's disease
BACKGROUND AND AIMS:
Crohn's disease (CD) can involve any part of the gastrointestinal tract. We aimed to characterize clinical, endoscopic, histologic features and treatment outcomes of CD patients with oesophageal involvement.
METHODS:
We collected cases through a retrospective multicentre European Crohn's and Colitis Organisation CONFER [COllaborative Network For Exceptionally Rare case reports] project. Clinical data were recorded in a standardized case report form.
RESULTS:
A total of 40 patients were reported [22 males, mean (±SD, range) age at oesophageal CD diagnosis: 25 (±13.3, 10-71) years and mean time of follow-up: 67 (±68.1, 3-240) months]. Oesophageal involvement was established at CD diagnosis in 26 patients (65%) and during follow-up in 14. CD was exclusively located in the oesophagus in 2 patients. Thirteen patients (32.2%) were asymptomatic at oesophageal disease diagnosis. Oesophageal strictures were present in 5 patients and fistulizing oesophageal disease in one. Eight patients exhibited granulomas on biopsies. Proton-pump inhibitors (PPIs) were administered in 37 patients (92.5%). Three patients underwent endoscopic dilation for symptomatic strictures and none oesophageal-related surgery. Diagnosis in pre-established CD resulted in treatment modifications in 9/14 patients. Clinical remission of oesophageal disease was seen in 33/40 patients (82.5%) after a mean time of 7 (±5.6, 1-18) months. Follow-up endoscopy was performed in 29/40 patients and 26/29 (89.7%) achieved mucosal healing.
CONCLUSION:
In this case series the endoscopic and histologic characteristics of isolated oesophageal CD were similar to those reported in other sites of involvement. Treatment was primarily conservative, with PPIs administered in the majority of patients and modifications in pre-existing IBD-related therapy occurring in two thirds of them. Clinical and endoscopic remission was achieved in more than 80% of the patients.info:eu-repo/semantics/publishedVersio
Supercurrent in Nb/InAs-Nanowire/Nb Josephson junctions
We report on the fabrication and measurements of planar mesoscopic Josephson
junctions formed by InAs nanowires coupled to superconducting Nb terminals. The
use of Si-doped InAs-nanowires with different bulk carrier concentrations
allowed to tune the properties of the junctions. We have studied the junction
characteristics as a function of temperature, gate voltage, and magnetic field.
In junctions with high doping concentrations in the nanowire Josephson
supercurrent values up to 100\,nA are found. Owing to the use of Nb as
superconductor the Josephson coupling persists at temperatures up to 4K. In all
junctions the critical current monotonously decreased with the magnetic field,
which can be explained by a recently developed theoretical model for the
proximity effect in ultra-small Josephson junctions. For the low-doped
Josephson junctions a control of the critical current by varying the gate
voltage has been demonstrated. We have studied conductance fluctuations in
nanowires coupled to superconducting and normal metal terminals. The
conductance fluctuation amplitude is found to be about 6 times larger in
superconducting contacted nanowires. The enhancement of the conductance
fluctuations is attributed to phase-coherent Andreev reflection as well as to
the large number of phase-coherent channels due to the large superconducting
gap of the Nb electrodes.Comment: 5 Figure, submitted to Journal of Applied Physic
Method for Accuracy Assessment of the Length Measurement Unit of Laser Tracking Systems
Laser tracking systems are widely used in large-scale metrology of geometric quantities. Their importance is confirmed by the fact that one of the parts of the ISO 10360 series of standards has been devoted to the issue of assessing their accuracy (ISO 10360-10). A laser tracker is a device whose final measurement result is calculated using indications from various subsystems included in it, such as devices for measuring length and angle. The analysis of these individual impacts can be useful in creating simulation models of accuracy which, in regard to the Industry 4.0 concept, seem to be the most justified in terms of speed of operation and ease of use. For this reason, it may be particularly important to undertake research on the accuracy of this component in isolation from other factors affecting the measurement of the coordinates of the point. The article describes a method that allows separation of the length measurement error from the other components. The method uses a high-accuracy interferometer which is treated as a reference system that allows for the comparison of indications obtained using the tested distance measurement system. Thanks to the proposed method, it is possible to minimize errors from the optical system and other measuring systems. The use of a precise linear guide allows the reduction of errors related to the implementation of linear motion. The article presents the test method and the results obtained from performed experiments, as well as formulates conclusions and the directions of further development
Method for Accuracy Assessment of the Length Measurement Unit of Laser Tracking Systems
Laser tracking systems are widely used in large-scale metrology of geometric quantities. Their importance is confirmed by the fact that one of the parts of the ISO 10360 series of standards has been devoted to the issue of assessing their accuracy (ISO 10360-10). A laser tracker is a device whose final measurement result is calculated using indications from various subsystems included in it, such as devices for measuring length and angle. The analysis of these individual impacts can be useful in creating simulation models of accuracy which, in regard to the Industry 4.0 concept, seem to be the most justified in terms of speed of operation and ease of use. For this reason, it may be particularly important to undertake research on the accuracy of this component in isolation from other factors affecting the measurement of the coordinates of the point. The article describes a method that allows separation of the length measurement error from the other components. The method uses a high-accuracy interferometer which is treated as a reference system that allows for the comparison of indications obtained using the tested distance measurement system. Thanks to the proposed method, it is possible to minimize errors from the optical system and other measuring systems. The use of a precise linear guide allows the reduction of errors related to the implementation of linear motion. The article presents the test method and the results obtained from performed experiments, as well as formulates conclusions and the directions of further development
Measurement properties of the Inventory of Cognitive Bias in Medicine (ICBM)
© 2008 Sladek et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background
Understanding how doctors think may inform both undergraduate and postgraduate medical education. Developing such an understanding requires valid and reliable measurement tools. We examined the measurement properties of the Inventory of Cognitive Bias in Medicine (ICBM), designed to tap this domain with specific reference to medicine, but with previously questionable measurement properties.
Methods
First year postgraduate entry medical students at Flinders University, and trainees (postgraduate doctors in any specialty) and consultants (N = 348) based at two teaching hospitals in Adelaide, Australia, completed the ICBM and a questionnaire measuring thinking styles (Rational Experiential Inventory).
Results
Questions with the lowest item-total correlation were deleted from the original 22 item ICBM, although the resultant 17 item scale only marginally improved internal consistency (Cronbach's α = 0.61 compared with 0.57). A factor analysis identified two scales, both achieving only α = 0.58. Construct validity was assessed by correlating Rational Experiential Inventory scores with the ICBM, with some positive correlations noted for students only, suggesting that those who are naïve to the knowledge base required to "successfully" respond to the ICBM may profit by a thinking style in tune with logical reasoning.
Conclusion
The ICBM failed to demonstrate adequate content validity, internal consistency and construct validity. It is unlikely that improvements can be achieved without considered attention to both the audience for which it is designed and its item content. The latter may need to involve both removal of some items deemed to measure multiple biases and the addition of new items in the attempt to survey the range of biases that may compromise medical decision making
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