311 research outputs found
Conjugatable water-soluble Pt(ii) and Pd(ii) porphyrin complexes: Novel nano- and molecular probes for optical oxygen tension measurement in tissue engineering
Measurement of oxygen tension in compressed collagen sheets was performed using matrix-embedded optical oxygen sensors based on platinum(II) and palladium(II) porphyrins supported on polyacrylamide nanoparticles. Bespoke, fully water-soluble, mono-functionalised Pt(II) and Pd(II) porphyrin complexes designed for conjugation under mild conditions were obtained using microwave-assisted metallation. The new sensors display a linear response (1/Ï vs. Oâ) to varying oxygen tension over a biologically relevant range (7.0 Ă 10â»âŽ to 2.7 Ă 10â»Âč mM) in aqueous solutions; a behaviour that is maintained following conjugation to polyacrylamide nanoparticles, and following embedding of the nanosensors in compressed collagen sheets, paving the way to innovative approaches for real-time resolution of oxygen gradients throughout 3D matrices useful for tissue regeneration
Notes on the integration of numerical relativity waveforms
A primary goal of numerical relativity is to provide estimates of the wave
strain, , from strong gravitational wave sources, to be used in detector
templates. The simulations, however, typically measure waves in terms of the
Weyl curvature component, . Assuming Bondi gauge, transforming to the
strain reduces to integration of twice in time. Integrations
performed in either the time or frequency domain, however, lead to secular
non-linear drifts in the resulting strain . These non-linear drifts are not
explained by the two unknown integration constants which can at most result in
linear drifts. We identify a number of fundamental difficulties which can arise
from integrating finite length, discretely sampled and noisy data streams.
These issues are an artifact of post-processing data. They are independent of
the characteristics of the original simulation, such as gauge or numerical
method used. We suggest, however, a simple procedure for integrating numerical
waveforms in the frequency domain, which is effective at strongly reducing
spurious secular non-linear drifts in the resulting strain.Comment: 23 pages, 10 figures, matches final published versio
Advancements in the co-formulation of biologic therapeutics
Biologic therapeutics are the medicines of the future and are destined to transform the approaches by which the causes and symptoms of diseases are cured and alleviated. These approaches will be accelerated through the development of novel strategies that target multiple pharmacologically active sites using a combination of different biologics, or mixtures of biologics and small molecule therapeutics. However, for this potential to be realised, advancements in co-formulation strategies for biologic therapeutics must be established. This review describes the current and emerging developments within this field and highlights the challenges and potential solutions, that will pave-the-way towards their clinical translation
Ninja data analysis with a detection pipeline based on the Hilbert-Huang Transform
The Ninja data analysis challenge allowed the study of the sensitivity of
data analysis pipelines to binary black hole numerical relativity waveforms in
simulated Gaussian noise at the design level of the LIGO observatory and the
VIRGO observatory. We analyzed NINJA data with a pipeline based on the Hilbert
Huang Transform, utilizing a detection stage and a characterization stage:
detection is performed by triggering on excess instantaneous power,
characterization is performed by displaying the kernel density enhanced (KD)
time-frequency trace of the signal. Using the simulated data based on the two
LIGO detectors, we were able to detect 77 signals out of 126 above SNR 5 in
coincidence, with 43 missed events characterized by signal to noise ratio SNR
less than 10. Characterization of the detected signals revealed the merger part
of the waveform in high time and frequency resolution, free from time-frequency
uncertainty. We estimated the timelag of the signals between the detectors
based on the optimal overlap of the individual KD time-frequency maps, yielding
estimates accurate within a fraction of a millisecond for half of the events. A
coherent addition of the data sets according to the estimated timelag
eventually was used in a characterization of the event.Comment: Accepted for publication in CQG, special issue NRDA proceedings 200
Defining Professionalism for Mental Health Services : A Rapid Systematic Review
Background: Efforts have been made to define professionalism across the professions, yet little attention has been paid to the concept in mental health services, where patientsâ needs differ to that in other healthcare specialties. Aims: To derive a definition of professionalism for mental health services using the existing literature. Method: A rapid, systematic review was conducted to identify empirical and non-empirical records that described professionalism in a mental health service context from 2006 to 2017. Studies were synthesised narratively using thematic analysis. Results: Seventy records were included in the review. Professionalism was described on two levels; at a societal level, a dynamic social contract between professions and society, and; at an individual level, having intrapersonal, interpersonal, and working professionalism. Utilising emerging themes, an operationalised definition of professionalism, suitable for a mental health service context was derived. Conclusions: Within mental health services, emphasis is placed on the interpersonal aspects of practice such as communication skills, maintaining boundaries and humanity. Themes relating to the vulnerability of patients and the challenge of supporting autonomy and choice whilst maintaining safety and acting in a clientâs best interest are also evident. âPractical wisdomâ and a flexible approach to working are needed to manage these challenging situations
Orthogonally bifunctionalised polyacrylamide nanoparticles: a support for the assembly of multifunctional nanodevices
Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper- catalysed azide-alkyne cycloaddition and isothiocyanate chemistry
Connecting Numerical Relativity and Data Analysis of Gravitational Wave Detectors
Gravitational waves deliver information in exquisite detail about
astrophysical phenomena, among them the collision of two black holes, a system
completely invisible to the eyes of electromagnetic telescopes. Models that
predict gravitational wave signals from likely sources are crucial for the
success of this endeavor. Modeling binary black hole sources of gravitational
radiation requires solving the Eintein equations of General Relativity using
powerful computer hardware and sophisticated numerical algorithms. This
proceeding presents where we are in understanding ground-based gravitational
waves resulting from the merger of black holes and the implications of these
sources for the advent of gravitational-wave astronomy.Comment: Appeared in the Proceedings of 2014 Sant Cugat Forum on Astrophysics.
Astrophysics and Space Science Proceedings, ed. C.Sopuerta (Berlin:
Springer-Verlag
Triangulation of gravitational wave sources with a network of detectors
There is significant benefit to be gained by pursuing multi-messenger
astronomy with gravitational wave and electromagnetic observations. In order to
undertake electromagnetic follow-ups of gravitational wave signals, it will be
necessary to accurately localize them in the sky. Since gravitational wave
detectors are not inherently pointing instruments, localization will occur
primarily through triangulation with a network of detectors. We investigate the
expected timing accuracy for observed signals and the consequences for
localization. In addition, we discuss the effect of systematic uncertainties in
the waveform and calibration of the instruments on the localization of sources.
We provide illustrative results of timing and localization accuracy as well as
systematic effects for coalescing binary waveforms.Comment: 20 pages, 5 figure
Data Analysis Challenges for the Einstein Telescope
The Einstein Telescope is a proposed third generation gravitational wave
detector that will operate in the region of 1 Hz to a few kHz. As well as the
inspiral of compact binaries composed of neutron stars or black holes, the
lower frequency cut-off of the detector will open the window to a number of new
sources. These will include the end stage of inspirals, plus merger and
ringdown of intermediate mass black holes, where the masses of the component
bodies are on the order of a few hundred solar masses. There is also the
possibility of observing intermediate mass ratio inspirals, where a stellar
mass compact object inspirals into a black hole which is a few hundred to a few
thousand times more massive. In this article, we investigate some of the data
analysis challenges for the Einstein Telescope such as the effects of increased
source number, the need for more accurate waveform models and the some of the
computational issues that a data analysis strategy might face.Comment: 18 pages, Invited review for Einstein Telescope special edition of
GR
Characteristic extraction in numerical relativity: binary black hole merger waveforms at null infinity
The accurate modeling of gravitational radiation is a key issue for
gravitational wave astronomy. As simulation codes reach higher accuracy,
systematic errors inherent in current numerical relativity wave-extraction
methods become evident, and may lead to a wrong astrophysical interpretation of
the data. In this paper, we give a detailed description of the
Cauchy-characteristic extraction technique applied to binary black hole
inspiral and merger evolutions to obtain gravitational waveforms that are
defined unambiguously, that is, at future null infinity. By this method we
remove finite-radius approximations and the need to extrapolate data from the
near zone. Further, we demonstrate that the method is free of gauge effects and
thus is affected only by numerical error. Various consistency checks reveal
that energy and angular momentum are conserved to high precision and agree very
well with extrapolated data. In addition, we revisit the computation of the
gravitational recoil and find that finite radius extrapolation very well
approximates the result at \scri. However, the (non-convergent) systematic
differences to extrapolated data are of the same order of magnitude as the
(convergent) discretisation error of the Cauchy evolution hence highlighting
the need for correct wave-extraction.Comment: 41 pages, 8 figures, 2 tables, added references, fixed typos. Version
matches published version
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