2,486 research outputs found
Trajectory Deflection of Spinning Magnetic Microparticles, the Magnus Effect at the Microscale
The deflection due to the Magnus force of magnetic particles with a diameter
of 80 micrometer dropping through fluids and rotating in a magnetic field was
measured. With Reynolds number for this experiment around 1, we found
trajectory deflections of the order of 1 degree, in agreement within
measurement error with theory. This method holds promise for the sorting and
analysis of the distribution in magnetic moment and particle diameter of
suspensions of microparticles, such as applied in catalysis, or objects loaded
with magnetic particles.Comment: 12 pages, 3 figures. Appendix with 6 figure
Composition profiling InAs quantum dots and wetting layers by atom probe tomography and cross-sectional scanning tunnelling microscopy
This study compares cross-sectional scanning tunnelling microscopy (XSTM) and
atom probe tomography (APT). We use epitaxially grown self-assembled InAs
quantum dots (QDs) in GaAs as an exemplary material with which to compare these
two nanostructural analysis techniques. We studied the composition of the
wetting layer and the QDs, and performed quantitative comparisons of the indium
concentration profiles measured by each method. We show that computational
models of the wetting layer and the QDs, based on experimental data, are
consistent with both analytical approaches. This establishes a link between the
two techniques and shows their complimentary behaviour, an advantage which we
exploit in order to highlight unique features of the examined QD material.Comment: Main article: 8 pages, 6 figures. Appendix: 3 pages, 5 figure
Shape control of QDs studied by cross-sectional scanning tunneling microscopy
In this cross-sectional scanning tunneling microscopy study we investigated
various techniques to control the shape of self-assembled quantum dots (QDs)
and wetting layers (WLs). The result shows that application of an indium flush
during the growth of strained InGaAs/GaAs QD layers results in flattened QDs
and a reduced WL. The height of the QDs and WLs could be controlled by varying
the thickness of the first capping layer. Concerning the technique of antimony
capping we show that the surfactant properties of Sb result in the preservation
of the shape of strained InAs/InP QDs during overgrowth. This could be achieved
by both a growth interrupt under Sb flux and capping with a thin GaAsSb layer
prior to overgrowth of the uncapped QDs. The technique of droplet epitaxy was
investigated by a structural analysis of strain free GaAs/AlGaAs QDs. We show
that the QDs have a Gaussian shape, that the WL is less than 1 bilayer thick,
and that minor intermixing of Al with the QDs takes place.Comment: 7 pages, 10 figure
Maternal and Paternal Risk Factors for Cryptorchidism and Hypospadias: A Case–Control Study in Newborn Boys
Little is known on environmental risk factors for cryptorchidism and hypospadias, which are among the most frequent congenital abnormalities. The aim of our study was to identify risk factors for cryptorchidism and hypospadias, with a focus on potential endocrine disruptors in parental diet and occupation. In a case–control study nested within a cohort of 8,698 male births, we compared 78 cryptorchidism cases and 56 hypospadias cases with 313 controls. The participation rate was 85% for cases and 68% for controls. Through interviews, information was collected on pregnancy aspects and personal characteristics, lifestyle, occupation, and dietary phytoestrogen intake of both parents. Occupational exposure to potential endocrine disruptors was classified based on self-reported exposure and ratings of occupational hygienists based on job descriptions. Our findings indicate that paternal pesticide exposure was associated with cryptorchidism [odds ratio (OR) = 3.8; 95% confidence interval (95% CI), 1.1–13.4]. Smoking of the father was associated with hypospadias (OR = 3.8; 95% CI, 1.8–8.2). Maternal occupational, dietary, and lifestyle exposures were not associated with either abnormality. Both abnormalities were associated with suboptimal maternal health, a lower maternal education, and a Turkish origin of the parents. Being small for gestational age was a risk factor for hypospadias, and preterm birth was a risk factor for cryptorchidism. Because paternal pesticide exposure was significantly associated with cryptorchidism and paternal smoking was associated with hypospadias in male offspring, paternal exposure should be included in further studies on cryptorchidism and hypospadias risk factors
Организационная модель аудита доходов санаторно-курортных предприятий
Целью статьи является определение сущности с учетом взглядов ученых и обоснование особенностей организационной модели аудита доходов санаторно-курортных организаций.Метою статті є визначення суті з урахуванням поглядів учених і обґрунтування особливостей організаційної моделі аудиту доходів санаторно-курортних організацій
Some thoughts about nonequilibrium temperature
The main objective of this paper is to show that, within the present
framework of the kinetic theoretical approach to irreversible thermodynamics,
there is no evidence that provides a basis to modify the ordinary Fourier
equation relating the heat flux in a non-equilibrium steady state to the
gradient of the local equilibrium temperature. This fact is supported, among
other arguments, through the kinetic foundations of generalized hydrodynamics.
Some attempts have been recently proposed asserting that, in the presence of
non-linearities of the state variables, such a temperature should be replaced
by the non-equilibrium temperature as defined in Extended Irreversible
Thermodynamics. In the approximations used for such a temperature there is so
far no evidence that sustains this proposal.Comment: 13 pages, TeX, no figures, to appear in Mol. Phy
Shape control of QDs studied by cross-sectional scanning tunneling microscopy
In this cross-sectional scanning tunneling microscopy study we investigated
various techniques to control the shape of self-assembled quantum dots (QDs)
and wetting layers (WLs). The result shows that application of an indium flush
during the growth of strained InGaAs/GaAs QD layers results in flattened QDs
and a reduced WL. The height of the QDs and WLs could be controlled by varying
the thickness of the first capping layer. Concerning the technique of antimony
capping we show that the surfactant properties of Sb result in the preservation
of the shape of strained InAs/InP QDs during overgrowth. This could be achieved
by both a growth interrupt under Sb flux and capping with a thin GaAsSb layer
prior to overgrowth of the uncapped QDs. The technique of droplet epitaxy was
investigated by a structural analysis of strain free GaAs/AlGaAs QDs. We show
that the QDs have a Gaussian shape, that the WL is less than 1 bilayer thick,
and that minor intermixing of Al with the QDs takes place.Comment: 7 pages, 10 figure
Two-stage model-based design of cancer phase I dose escalation trials: evaluation using the phase I program of barasertib (AZD1152)
Introduction Modeling and simulation of pharmacokinetics and pharmacodynamics has previously been shown to be potentially useful in designing Phase I programs of novel anti-cancer agents that show hematological toxicity. In this analysis, a two-stage model-based trial design was evaluated retrospectively using data from the Phase I program with the aurora kinase inhibitor barasertib. Methods Data from two Phase I trials and four regimens were used (n = 79). Using barasertib-hydroxy QPA plasma concentrations and neutrophil count data from only study 1A, a PKPD model was developed and subsequently used to predict the MTD and a safe starting dose for the other trials. Results The PKPD model based on data from the first study adequately described the time course of neutrophil count fluctuation. The two-stage model-based design provided safe starting doses for subsequent phase I trials for barasertib. Predicted safe starting dose levels were higher than those used in two subsequent trials, but lower than used in the other trial. Discussion The two-stage approach could have been applied safely to define starting doses for alternative dosing strategies with barasertib. The limited improvement in efficiency for the phase I program of barasertib may have been due to the fact that starting doses for the studied phase I trials were already nearly optimal. Conclusion Application of the two-stage model-based trial design in Phase I programs with novel anti-cancer drugs that cause haematological toxicity is feasible, safe, and may lead to a reduction in the number of patient treated at sub-therapeutic dose-levels
EQUIVALENCES BETWEEN STOCHASTIC SYSTEMS
Time-dependent correlation functions of (unstable) particles undergoing
biased or unbiased diffusion, coagulation and annihilation are calculated. This
is achieved by similarity transformations between different stochastic models
and between stochastic and soluble {\em non-stochastic} models. The results
agree with experiments on one-dimensional annihilation-coagulation processes.Comment: 15 pages, Latex. Some corrections made and an appendix adde
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