1,696 research outputs found
Corrected confidence intervals for secondary parameters following sequential tests
Corrected confidence intervals are developed for the mean of the second
component of a bivariate normal process when the first component is being
monitored sequentially. This is accomplished by constructing a first
approximation to a pivotal quantity, and then using very weak expansions to
determine the correction terms. The asymptotic sampling distribution of the
renormalised pivotal quantity is established in both the case where the
covariance matrix is known and when it is unknown. The resulting approximations
have a simple form and the results of a simulation study of two well-known
sequential tests show that they are very accurate. The practical usefulness of
the approach is illustrated by a real example of bivariate data. Detailed
proofs of the main results are provided.Comment: Published at http://dx.doi.org/10.1214/074921706000000617 in the IMS
Lecture Notes--Monograph Series
(http://www.imstat.org/publications/lecnotes.htm) by the Institute of
Mathematical Statistics (http://www.imstat.org
Theoretical and experimental studies of the underlying processes and techniques of low pressure measurement Letter report, 1 Jul. 1967 - 31 May 1968
Ionization gage behavior in various gas mixtures and atmospheric composition
Theoretical and experimental studies of the underlying processes and techniques of low pressure measurement Progress report, 1 Jun. 1966 - 31 May 1967
Construction, testing, and refining of vacuum gauges - ionization gauge cross section ratio
Surface grafting of electrospun fibers using ATRP and RAFT for the control of biointerfacial interactions
BACKGROUND The ability to present signalling molecules within a low fouling 3D environment that mimics the extracellular matrix is an important goal for a range of biomedical applications, both in vitro and in vivo. Cell responses can be triggered by non-specific protein interactions occurring on the surface of a biomaterial, which is an undesirable process when studying specific receptor-ligand interactions. It is therefore useful to present specific ligands of interest to cell surface receptors in a 3D environment that minimizes non-specific interactions with biomolecules, such as proteins. METHOD In this study, surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol)-based monomers was carried out from the surface of electrospun fibers composed of a styrene/vinylbenzyl chloride copolymer. Surface initiated radical addition-fragmentation chain transfer (SI-RAFT) polymerisation was also carried out to generate bottle brush copolymer coatings consisting of poly(acrylic acid) and poly(acrylamide). These were grown from surface trithiocarbonate groups generated from the chloromethyl styrene moieties existing in the original synthesised polymer. XPS was used to characterise the surface composition of the fibers after grafting and after coupling with fluorine functional XPS labels. RESULTS Bottle brush type coatings were able to be produced by ATRP which consisted of poly(ethylene glycol) methacrylate and a terminal alkyne-functionalised monomer. The ATRP coatings showed reduced non-specific protein adsorption, as a result of effective PEG incorporation and pendant alkynes groups existing as part of the brushes allowed for further conjugation of via azide-alkyne Huisgen 1,3-dipolar cycloaddition. In the case of RAFT, carboxylic acid moieties were effectively coupled to an amine label via amide bond formation. In each case XPS analysis demonstrated that covalent immobilisation had effectively taken place. CONCLUSION Overall, the studies presented an effective platform for the preparation of 3D scaffolds which contain effective conjugation sites for attachment of specific bioactive signals of interest, as well as actively reducing non-specific protein interactions.This research was supported by the Cooperative Research Centre for
Polymers (CRCP)
Plasma polymerization for biomedical applications: A review
Plasma polymers have long been of interest as thin film coatings on biomedical devices and products, to generate desirable surface properties for favorable bio-interfacial interactions. Plasma polymers have also been used as platforms for the covalent immobilization of bioactive molecules. More recently, additional aspects have been investigated, such as selective prevention of adhesion of microbial pathogens, either via plasma polymers per se or including antimicrobial drugs. Plasma polymers have also been investigated for the release of silver ions and small organic molecules. Complementing low-pressure plasma approaches, processes at atmospheric pressure have attracted interest recently, including for nano/biocomposite coatings. This contribution reviews the use of plasma polymers for intended biomedical applications, with a focus on more recent topic areas
Quark propagator in Landau and Laplacian gauges with overlap fermions
The properties of the momentum space quark propagator in Landau gauge and Gribov copy free Laplacian gauge are studied for the overlap quark action in quenched lattice QCD. Numerical calculations are done on two lattices with different lattice spacing a and the same physical volume. We have calculated the nonperturbative wave-function renormalization function Z(q) and the nonperturbative mass function M(p) for a variety of bare quark masses and perform a simple linear extrapolation to the chiral limit. We focus on the comparison of the behavior of Z(q) and M(p) in the chiral limit in the two gauge fixing schemes as well as the behavior on two lattices with different lattice spacing a. We find that the mass functions M(p) are very similar for the two gauges while the wave-function renormalization function Z(q) is more strongly infrared suppressed in the Laplacian gauge than in the Landau gauge on the finer lattice. For Laplacian gauge, it seems that the finite a error is large on the coarse lattice which has a lattice spacing a of about 0.124 fm.J. B. Zhang, Patrick O. Bowman, Ryan J. Coad, Urs M. Heller, Derek B. Leinweber, and Anthony G. Williams (CSSM Lattice Collaboration
Guidance for better governance towards a sustainable, participatory and inclusive wild meat sector.
Agenda item 4 at the twenty-first meeting of the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) established under Article 25 of the Convention will be held in Montreal, Canada, at the Palais des Congrès, from 11 to 14 December 2017
Towards the architecture of an instructional multimedia database
The applicability of multimedia databases in education may be extended if they can serve multiple target groups, leading to affordable costs per unit for the user. In this contribution, an approach is described to build generic multimedia databases to serve that purpose. This approach is elaborated within the ODB Project ('Instructional Design of an Optical DataBase'); the term optical refers to the use of optical storage media to hold the audiovisual components. The project aims at developing a database in which a hypermedia encyclopedia is combined with instructional multimedia applications for different target groups at different educational levels. The architecture of the Optical Database will allow for switching between application types while working (for instance from tutorial instruction via the encyclopedia to a simulation and back). For instruction, the content of the database is thereby organized around so-called standard instruction routes: one route per target group. In the project, the teacher is regarded as the manager of instruction.\ud
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From that perspective, the database is primarily organized as a teaching facility. Central to the research is the condition that the architecture of the Optical Database has to enable teachers to select and tailor instruction routes to their needs in a way that is perceived as logical and easy to use
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