3,159 research outputs found
Strategies for preparing fluorescently labelled polymer nanoparticles
There is great interest in the use of fluorescent polymer nanoparticles as optical imaging agents. When designing and synthesising a fluorescent polymer nanoparticle imaging agent there is a large variety in both the particle formation and dye attachment strategies that can be pursued. In this mini-review we detail this range of possibilities, illustrating with examples from the literature, and highlighting particular advantages in each case. © 2014 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
Precise calibration of LIGO test mass actuators using photon radiation pressure
Precise calibration of kilometer-scale interferometric gravitational wave
detectors is crucial for source localization and waveform reconstruction. A
technique that uses the radiation pressure of a power-modulated auxiliary laser
to induce calibrated displacements of one of the ~10 kg arm cavity mirrors, a
so-called photon calibrator, has been demonstrated previously and has recently
been implemented on the LIGO detectors. In this article, we discuss the
inherent precision and accuracy of the LIGO photon calibrators and several
improvements that have been developed to reduce the estimated voice coil
actuator calibration uncertainties to less than 2 percent (1-sigma). These
improvements include accounting for rotation-induced apparent length variations
caused by interferometer and photon calibrator beam centering offsets, absolute
laser power measurement using temperature-controlled InGaAs photodetectors
mounted on integrating spheres and calibrated by NIST, minimizing errors
induced by localized elastic deformation of the mirror surface by using a
two-beam configuration with the photon calibrator beams symmetrically displaced
about the center of the optic, and simultaneously actuating the test mass with
voice coil actuators and the photon calibrator to minimize fluctuations caused
by the changing interferometer response. The photon calibrator is able to
operate in the most sensitive interferometer configuration, and is expected to
become a primary calibration method for future gravitational wave searches.Comment: 13 pages, 6 figures, accepted by Classical and Quantum Gravit
Precise calibration of LIGO test mass actuators using photon radiation pressure
Precise calibration of kilometer-scale interferometric gravitational wave
detectors is crucial for source localization and waveform reconstruction. A
technique that uses the radiation pressure of a power-modulated auxiliary laser
to induce calibrated displacements of one of the ~10 kg arm cavity mirrors, a
so-called photon calibrator, has been demonstrated previously and has recently
been implemented on the LIGO detectors. In this article, we discuss the
inherent precision and accuracy of the LIGO photon calibrators and several
improvements that have been developed to reduce the estimated voice coil
actuator calibration uncertainties to less than 2 percent (1-sigma). These
improvements include accounting for rotation-induced apparent length variations
caused by interferometer and photon calibrator beam centering offsets, absolute
laser power measurement using temperature-controlled InGaAs photodetectors
mounted on integrating spheres and calibrated by NIST, minimizing errors
induced by localized elastic deformation of the mirror surface by using a
two-beam configuration with the photon calibrator beams symmetrically displaced
about the center of the optic, and simultaneously actuating the test mass with
voice coil actuators and the photon calibrator to minimize fluctuations caused
by the changing interferometer response. The photon calibrator is able to
operate in the most sensitive interferometer configuration, and is expected to
become a primary calibration method for future gravitational wave searches.Comment: 13 pages, 6 figures, accepted by Classical and Quantum Gravit
On designing observers for time-delay systems with nonlinear disturbances
This is the post print version of the article. The official published version can be obtained from the link below - Copyright 2002 Taylor & Francis LtdIn this paper, the observer design problem is studied for a class of time-delay nonlinear systems. The system under consideration is subject to delayed state and non-linear disturbances. The time-delay is allowed to be time-varying, and the non-linearities are assumed to satisfy global Lipschitz conditions. The problem addressed is the design of state observers such that, for the admissible time-delay as well as non-linear disturbances, the dynamics of the observation error is globally exponentially stable. An effective algebraic matrix inequality approach is developed to solve the non-linear observer design problem. Specifically, some conditions for the existence of the desired observers are derived, and an explicit expression of desired observers is given in terms of some free parameters. A simulation example is included to illustrate the practical applicability of the proposed theory.The work of Z. Wang was supported in part by the University of Kaiserslautern of Germany and the Alexander von Humboldt Foundation of Germany
Making sense of business analytics : the case of two start-ups
Business analytics have enabled businesses to leverage unstructured and dispersed data in order to improve their operations and position themselves better within a highly turbulent environment. While much discussion has been focused on how businesses can move from data to insights to decision making, much less is known around how businesses actually interpret the insights provided by business analytics tools. This extended abstract proposes the use of sense-making as the theoretical lens for interpreting these insights, combined with contextual information. We will be using two case studies to further explore the applicability of our proposition
Inverse scattering approach to multiwavelength Fabry-Pérot laser design
A class of multiwavelength Fabry-Pérot lasers is introduced where the spectrum is tailored through a patterning of the cavity effective index. The cavity geometry is obtained using an inverse scattering approach and can be designed such that the spacing of discrete Fabry-Pérot lasing modes is limited only by the bandwidth of the inverted gain medium. A specific two-color semiconductor laser with a mode spacing in the THz region is designed, and measurements are presented demonstrating the simultaneous oscillation of the two wavelengths. The nonperiodic effective index profile of the particular two-color device considered is shown to be related to a Moiré or superstructure grating
Technology adoption in the BIM implementation for lean architectural practice
Justification for Research: the construction companies are facing barriers and challenges in BIM adoption as there is no clear guidance or best practice studies from which they can learn and build up their capacity for BIM use in order to increase productivity, efficiency, quality, and to attain competitive advantages in the global market and to achieve the targets in environmental sustainability.
Purpose: this paper aims to explain a comprehensive and systemic evaluation and assessment of the relevant BIM technologies as part of the BIM adoption and implementation to demonstrate how efficiency gains have been achieved towards a lean architectural practice.
Design/Methodology/Approach: The research is undertaken through a KTP (Knowledge transfer Partnership) project between the University of Salford and the John McCall Architects based in Liverpool, which is an SME (Small Medium Enterprise). The overall aim of KTP is to develop Lean Design Practice through the BIM adoption and implementation. The overall BIM implementation approach uses a socio-technical view in which it does not only consider the implementation of technology but also considers the socio-cultural environment that provides the context for its implementation. The technology adoption methodology within the BIM implementation approach is the action research oriented qualitative and quantitative research for discovery, comparison, and experimentation as the KTP project with JMA provides an environment for “learning by doing”
Findings: research has proved that BIM technology adoption should be undertaken with a bottom-up approach rather than top-down approach for successful change management and dealing with the resistance to change. As a result of the BIM technology adoption, efficiency gains are achieved through the piloting projects and the design process is improved through the elimination of wastes and value generation.
Originality/Value: successful BIM adoption needs an implementation strategy. However, at operational level, it is imperative that professional guidelines are required as part of the implementation strategy. This paper introduces a systematic approach for BIM technology adoption based on a case study implementation and it demonstrates a guideline at operational level for other SME companies of architectural practices
Controlling the synthesis of degradable vinyl polymers by xanthate-mediated polymerization
The copolymerization of vinyl acetate (VAc) and 2-methylene-1,3-dioxepane (MDO), as well as the homopolymerization of MDO in the presence of a p-methoxyphenyl xanthate chain transfer agent (CTA) is reported and comparison of the homopolymerization of MDO with other known xanthates was also investigated. In depth investigation showed loss of the xanthate functionality was a result of Z-group fragmentation leading to the formation of carbonodithioate groups, as confirmed by 13C NMR spectroscopy. The use of the xanthate with a substituted phenyl Z-group drastically reduces fragmentation through the Z-group and hence significantly increases chain-end retention during the polymerization using the RAFT/MADIX technique. Post-polymerization modification of the chain-end of poly(MDO) was achieved by in situ aminolysis and base-catalyzed Michael addition of propargyl methacrylate onto the terminal thiol to form alkyne functional poly(MDO)
An immunotherapy survivor population: health-related quality of life and toxicity in patients with metastatic melanoma treated with immune checkpoint inhibitors
© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Purpose The immune checkpoint inhibitors (ICIs) have resulted in subgroups of patients with metastatic melanoma achievinghigh-quality durable responses. Metastatic melanoma survivors are a new population in the era of cancer survivorship. The aimofthis study was to evaluate metastatic melanoma survivors in terms of health-related quality of life (HRQoL), immune-relatedadverse events (irAEs) and exposure to immunosuppressive agents in a large single centre in the UK.Methods We defined the survivor population as patients with a diagnosis of metastatic melanoma who achieved a durableresponse to an ICI and had been followed-up for a minimum of 12 months from initiation of ICI without disease progression.HRQoL was assessed using SF-36. Electronic health records were accessed to collect data on demographics, treatments, irAEsand survival. HRQoL data was compared with two norm-based datasets.Results Eighty-four metastatic melanoma survivors were eligible and 87% (N = 73) completed the SF-36. ICI-related toxicity ofany grade occurred in 92%of patients and 43%had experienced a grade 3 or 4 toxicity. Almost half (49%) of the patients requiredsteroids for the treatment of ICI-related toxicity, whilst 14% required treatment with an immunosuppressive agent beyondsteroids.Melanoma survivors had statistically significant lower HRQoL scores with regard to physical, social and physical rolefunctioning and general health compared with the normative population. There was a trend towards inferior scores in patientswith previous exposure to ipilimumab compared with those never exposed to ipilimumab.Conclusions Our results show that metastatic melanoma survivors have potentially experienced significant ICI-related toxicityand experience significant impairments in specific HRQoL domains. Future service planning is required to meet this population’sunique survivorship needs.Peer reviewe
The Prognostic Significance of the Preoperative Full Blood Count after Resection of Colorectal Liver Metastases
Introduction. Increased preoperative platelet and neutrophil counts are risk factors for decreased survival in several different malignancies. Our aim was to investigate the relationship between overall or disease-free survival after resection of CRLM and the preoperative haematological parameters.
Methods. We reviewed a cohort of 140 patients who underwent resection of CRLM with curative intent, utilising prospectively maintained databases. Patient demographics, operative details, FBC, CRP, INR, histopathology results, and survival data were examined. Kaplan-Meier survival and Cox regression analyses were used to determine the impact of all variables on survival.
Results. 140 patients (96 males) with a median age of 67 years (range 33–82 years) underwent resection of CRLM. A significant correlation was exhibited between preoperative platelet count and neutrophil count (rho = 0.186, P = .028). When modelled as continuous covariates in a Cox regression hazards, an increased preoperative platelet (P = .02) and neutrophil counts (P ≤ .001) were significantly associated with overall survival. Of the haematological parameters assessed only preoperative platelet count showed a strong trend of association with disease free survival; however this failed to reach statistical significance (P = .076). Conclusions. Increased preoperative platelet and neutrophil counts are independent risk factors for decreased survival in patients undergoing resection of CRLM in our series of patients. These findings require validation in larger studies to determine their relationship with survival. Further research into the role of these cell types in tumour progression, particularly in the development and inhibition of angiogenesis, is warranted
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