5,568 research outputs found
Toward Hybrid Materials: Group Transfer Polymerization of 3-(Trimethoxysilyl)propyl Methacrylate
Front Cover: Group transfer polymerisation (GTP), a living polymerization technique that is easy to scale up, enables the one-pot fabrication of class-II hybrid materials. Specifically a star polymer is synthesized with a 3-(trimethoxy-silyl)propyl methacrylate, alkoxysilane group containing functional monomer. The polymer is then cross-linked to produce an organic-inorganic class-II hybrid material, which can be used in various applications such as thin films and biomaterials. Further details can be found in the article by J. J. Chung, J. R. Jones, and T. K. Georgiou* on page 1806
Crime data mining: A general framework and some examples
A general framework for crime data mining that draws on experience gained with the Coplink project at the University of Arizona is presented. By increasing efficiency and reducing errors, this scheme facilitates police work and enables investigators to allocate their time to other valuable tasks.published_or_final_versio
Estimating the population health impact of a multi-cancer early detection genomic blood test to complement existing screening in the US and UK
Background:
Multi-cancer early detection (MCED) next-generation-sequencing blood tests represent a potential paradigm shift in screening.
Methods:
We estimated the impact of screening in the US and UK. We used country-specific parameters for uptake, and test-specific sensitivity and false-positive rates for current screening: breast, colorectal, cervical and lung (US only) cancers. For the MCED test, we used cancer-specific sensitivities by stage. Outcomes included the true-positive:false-positive (TP:FP) ratio; and the cost of diagnostic investigations among screen positives, per cancer detected (Diagcost). Outcomes were estimated for recommended screening only, and then when giving the MCED test to anyone without cancer detected by current screening plus similarly aged adults ineligible for recommended screening.
Results:
In the US, current screening detects an estimated 189,498 breast, cervical, colorectal and lung cancers. An MCED test with 25–100% uptake detects an additional 105,526–422,105 cancers (multiple types). The estimated TP:FP (Diagcost) was 1.43 (7060) using an MCED test. For the UK the corresponding estimates were 1:18 (£10,452) for current screening, and 1:1.6 (£2175) using an MCED test.
Conclusions:
Adding an MCED blood test to recommended screening can potentially be an efficient strategy. Ongoing randomised studies are required for full efficacy and cost-effectiveness evaluations
On Global Flipped SU(5) GUTs in F-theory
We construct an SU(4) spectral divisor and its factorization of types (3,1)
and (2,2) based on the construction proposed in [1]. We calculate the chiral
spectra of flipped SU(5) GUTs by using the spectral divisor construction. The
results agree with those from the analysis of semi-local spectral covers. Our
computations provide an example for the validity of the spectral divisor
construction and suggest that the standard heterotic formulae are applicable to
the case of F-theory on an elliptically fibered Calabi-Yau fourfold with no
heterotic dual.Comment: 45 pages, 12 tables, 1 figure; typos corrected, footnotes added, and
a reference adde
Flipped SU(5) GUTs from E_8 Singularities in F-theory
In this paper we construct supersymmetric flipped SU(5) GUTs from E_8
singularities in F-theory. We start from an SO(10) singularity unfolded from an
E_8 singularity by using an SU(4) spectral cover. To obtain realistic models,
we consider (3,1) and (2,2) factorizations of the SU(4) cover. After turning on
the massless U(1)_X gauge flux, we obtain the SU(5) X U(1)_X gauge group. Based
on the well-studied geometric backgrounds in the literature, we demonstrate
several models and discuss their phenomenology.Comment: 46 pages, 23 tables, 1 figure, typos corrected, references added, and
new examples presente
Sequence learning in Associative Neuronal-Astrocytic Network
The neuronal paradigm of studying the brain has left us with limitations in
both our understanding of how neurons process information to achieve biological
intelligence and how such knowledge may be translated into artificial
intelligence and its most brain-derived branch, neuromorphic computing.
Overturning our fundamental assumptions of how the brain works, the recent
exploration of astrocytes is revealing that these long-neglected brain cells
dynamically regulate learning by interacting with neuronal activity at the
synaptic level. Following recent experimental evidence, we designed an
associative, Hopfield-type, neuronal-astrocytic network and analyzed the
dynamics of the interaction between neurons and astrocytes. We show that
astrocytes were sufficient to trigger transitions between learned memories in
the neuronal component of the network. Further, we mathematically derived the
timing of the transitions that was governed by the dynamics of the
calcium-dependent slow-currents in the astrocytic processes. Overall, we
provide a brain-morphic mechanism for sequence learning that is inspired by,
and aligns with, recent experimental findings. To evaluate our model, we
emulated astrocytic atrophy and showed that memory recall becomes significantly
impaired after a critical point of affected astrocytes was reached. This
brain-inspired and brain-validated approach supports our ongoing efforts to
incorporate non-neuronal computing elements in neuromorphic information
processing.Comment: 8 pages, 5 figure
An ex vivo porcine spleen perfusion as a model of bacterial sepsis
An ex vivo, porcine spleen perfusion model was established to study the early events occurring in the spleen prior to
the onset of bacterial sepsis, using organs retrieved from animals slaughtered for food production. Porcine spleens
were harvested from adult pigs and connected to a normothermic extracorporeal perfusion circuit. Constant perfusion
of heparinized blood was performed for 6 hours. After injection of Streptococcus pneumoniae to the circuit, serial
samples of both blood and spleen biopsies were collected and analyzed. Functionality of the perfused organs was
assessed by monitoring the blood-gas parameters, flow rate and filtering capability of the organ. Interestingly, we
observed full clearance of bacteria from the blood and an increase in bacterial counts in the spleen. Classical histology
and immunohistochemistry on biopsies also confirmed no major damage in the organ architecture and no changes in
the immune cell distribution other than the presence of clusters of pneumococci. A time-course study confirmed that each
focus of infection derived from the replication of single pneumococcal cells within splenic macrophages. The model
proposed – in line with the 3Rs principles – has utility in the replacement of experimental animals in infection research.
Murine models are prevalently used to study pneumococcal infections but are often not predictive for humans due to
substantial differences in the immune systems of the two species. This model is designed to overcome these limitations,
since porcine immunology, and splenic architecture in particular, closely resemble those of humans
Measuring Flexicurity: Precautionary Notes, a New Framework, and an Empirical Example
Recently, there has been an increase and abundance of literature measuring flexicurity across countries. However, there is yet to be any agreement on the definition of the key concepts of flexicurity as well as the framework in which to base one’s research. Due to this, the outcomes found in the existing studies are rather diverse, far from reaching a consensus, and can be misleading. This paper addresses the issues by first introducing a framework, namely, the various levels and stages of flexicurity, as well as introducing some key issues that should be addressed when doing flexicurity indicators research. In addition, an empirical example is given to show how the framework derived can be used to carry out flexicurity research, and to show how by not regarding these frameworks one can come to misleading outcomes
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